Physical Properties Of Glasses Research Articles

Investigation of structural, physical and optical properties of sodium boro-tellurite glasses doped with iron oxide

In this work, we demonstrate systematic studies on the influence of Fe2O3 on the structural and optical properties of transparent B2O3–TeO2–Na2O glasses containing the different concentrations of Fe2O3. The glasses were prepared via the standard melt quenching method, and the prepared glasses were characterized using, XRD, electron paramagnetic resonance (EPR), FTIR, and UV–visible spectroscopic techniques. Furthermore, we evaluated several physical properties of the glasses, including densities, molar volume, boron-boron separation, and oxygen packing density, with respect to the concentration of Fe2O3 in the host glass matrix. It is observed that the density of the glasses and the average boron-boron distance found increase with Fe2O3 concentration due to the modification in the glass network induced by the dopant ions. EPR spectra reveals the presence resonance signals at g ∼2.04 and g ∼4.26, hence it proves the existence of Fe3+ in distorted octahedral coordination and supported by UV–Vis absorption bands. The FTIR spectra revealed an increase in spectral intensity with the concentration of Fe2O3. This was attributed to the formation of non-bridging oxygens through converting BO4 units into BO3 units, which Fe2O3 mediated. The UV–visible spectral analysis showed a decreased energy band gap from 2.26 to 1.51 eV with increased Fe2O3 concentration. Additionally, we determined the Urbach energy, refractive index, optical basicity, and electronegativity, which are presented in detail.

Enhancing luminescence performance via adjusting the doping concentration and boron aluminum ratio in Dy3+ -activated barium-boroaluminosilicate glasses for laser and W-LED applications

A series of barium-boroaluminosilicate [30SiO2-11Al2O3-44B2O3-5BaO-(10-x)K2O-xDy2O3 (with x = 0.25, 0.5, 0.75, 1.0, 1.25, 1.5 mol%)] glasses doped with Dy3+ ions were prepared by the high temperature (melt quenching) method. In the glass matrix, the relationship among structure, luminescence properties, and B/Al ratio was analyzed; also studied are the physical properties of glass and influence of Dy3+ concentration on the luminescence properties. Differential Scanning Calorimeter (DSC) results have shown the glass matrix exhibiting good thermal stability and high resistance to crystallization. FTIR and Raman spectra have confirmed the presence of stretching and bending vibrations of [BO3], [AlO4] and [SiO4] structural units in the prepared glass. The observed UV–Vis–NIR spectra have indicated that the existence of thirteen bands corresponding to the transition Dy3+ ions from 6H15/2 level to different excited levels; the transmittance curves obtained have shown the transmittance up to 91 %. Increase in Dy3+ concentration is found to decrease the optical band gap; the calculated Judd-Oflet parameter is found to follow the trend Ω2＞Ω4＞Ω6. Photoluminescence studies have shown three emission peaks which could be associated to the transitions: 4F9/2 → 6H15/2 (blue light), 4F9/2 → 6H13/2 (yellow light), and 4F9/2 → 6H11/2 (red light); the maximum intensity obtained for the glass with x = 0.75 mol%, with spacing between Dy3+ ions being 1.9137 Å; and the decay curve could be fitted with double exponential function. The CIE results have revealed that the chromaticity coordinates are closer to that of standard white light, and the color temperature located in the region of cold white light.

Effect of Gamma Irradiation on Dielectric and AC Conductivity Studies of Bismuth Borate Glasses Doped with V2O5

Objectives: To study gamma ray irradiation effect on dielectric and AC conductivity of V2O5 doped bismuth borate glasses designed with the compositions 50B2O3-(50-X)Bi2O3-XV2O5 where, X = 0, 0.2, 0.4, 0.6, 0.8, 1.0 and establishing the conduction mechanism. Methods: Glasses were synthesized by traditional melt quenching technique at 1323K. The prepared samples were subjected to annealing at 623K, which helps to remove strain in the samples. Absence of crystalline phases in the samples was confirmed by X-ray diffraction studies. An independent measurement of dielectric constant, dielectric loss and AC conductivity was carried out for temperature range from 300Kto 493K by impedance analyzer. Findings: The physical properties of glass were achieved by studying the density and the molar volume. Dielectric constant (e ’) and dielectric loss (e ”) were measured as a function of temperatures in the range from 300K to 493K, over the frequencies 102 Hz – 106 Hz before and after gamma ray irradiation. AC conductivity (s AC) of the glasses was measured as a function of frequency for different temperatures before and after gamma ray irradiation. Novelty: For the first time, it was attempted that the effect of gamma ray irradiation on dielectric and AC conductivity properties of bismuth-borate glasses doped with vanadium oxide has been investigated. Here we have observed the change in the variation of dielectric constant, dielectric loss and AC conductivity with frequency and temperature before and after gamma ray irradiation. The borate network becomes more compact after being exposed to gamma rays, and the energy band gap may even narrow. Furthermore, it has been found that the composition of the glass influences how radiation impacts conductivity. Keywords: Oxide Glasses; XRD; Gamma Ray Irradiation; Dielectric Properties; AC Conductivity

APPLICATION OF ART GLASS IN INTERIORS OF PUBLIC BUILDINGS

The aim of the research is to identify the compositional methods of using art glass in the interiors of public buildings in order to increase their aesthetic expressiveness. In the article the information on the history of art glass development is given. According to the results of the historical analysis, it is concluded that new directions of glass application arose with the development of new technologies of glass production and processing - this process continues to this day. An overview of the state of study of the problem, in particular the research of Kazakova L.V., F.Petryakova, Som-Serdyukova O.M., Daineko V.V., and identified the main areas in which research is conducted. The physical properties of glass and its types by technological features are considered. A historical overview of the development of gutnitsy on the territory of Ukraine. The two main trends in studio glassmaking to date have been identified and a conclusion has been drawn about the evolution of art glass from the subject form to the art object. The current state of art glass formation is characterized by associativity, metaphoricalness, and increased decorativeness. The classification of art glass according to the function of application in public interior is carried out. The basic compositional methods of placing art glass in the space of public interior are revealed. Three degrees of integration of art glass with elements of architecture are formulated: the decor on architectural elements, as a part of architectural elements, is directly an architectural and constructive element. Examples of objects that demonstrate the integration of art glass with architectural elements are given. Henri Matisse's stained glass windows in the Dominican Sisters' Chapel in Mans, France, are described as an example of the use of the "rhythm" compositional technique and Dale Chihuly's glass garden gallery in Seattle with a glass installation that dominates the pavilion. It is concluded that the choice of compositional methods of including art glass in the interior space depends on many factors - the functional purpose of the room, the specifics of space, its size, etc. and should take into account aspects of its psychological impact on man, principles of structural and compositional organization and features life processes.

Development of co-doped Li2S-borate-based glass system as energy storage applications: X-ray absorption spectroscopy aspect

Li2S-2H3BO3: xCoN2O6.6H2O (x = 3, 4 and 5mol %) glass system was prepared. The microstructure and physical properties of glasses were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Vis spectrophotometer and vibrating sample magnetometer (VSM). In order to measure the electrochemical properties of glasses, the cycling voltammograms (CVs) was employed where the highest specific capacitances of 97.972 mV/s was obtained from x= 5mol%. For structure-function of glasses, the S and Co oxidation states at S K-edge and Co K-edge and local structure around Co ions were studied by X-ray absorption spectroscopy (XAS) including X-ray absorption near edge structure (XANES) and extended X-ray absorption spectroscopy (EXAFS). It was found that, the S6+ oxidation state and mixing Co2+/3+ were revealed, respectively. Moreover, the Co K-edge EXAFS fitting was exhibited co-existence of CoA-O bond (tetrahedral coordination) and CoB-O bond (octahedral coordination) in all fabricated glasses with a difference proportional site.

Effect of substitution of S for Se on structure and physical properties in Ge<sub>11.5</sub>As<sub>24</sub>Se<sub>64.5–<i>x</i></sub>S<i><sub>x</sub></i> glass

In this paper, chalcogenide glasses Ge<sub>11.5</sub>As<sub>24</sub>Se<sub>64.5–<i>x</i></sub>S<i><sub>x</sub></i> (<i>x</i> = 0, 16.125%, 32.25%, 48.375% and 64.5%) are prepared and their optical properties are studied in order to select the best components for the use in optical devices. The values of laser damage threshold, refractive index, and third-order nonlinear refractive index, as well as the absorption spectra of the glasses are measured. The results show that the linear and third-order nonlinear refractive indices of the glass decrease gradually, the glass optical band gap increases gradually, and the laser damage threshold increases continuously after the high threshold component S atoms have been introduced gradually. We further investigate the structural origins of these changes in physical properties by Raman scattering spectra and high resolution X-ray photoelectron spectroscopy. By analyzing the evolution process of different structural units in the glass, it is found that the heteropolar bonds (Ge—Se/S, As—Se/S) are dominant in these glass network structures, and compared with Se, and that Ge and As prefer to bond with S. As the ratio of S/Se increases, the number of chemical bonds related to Se (Ge—Se, As—Se and Se—Se) decreases gradually, while the number of chemical bonds related to Se (Ge—S, As—S and S—S) increases gradually, which has little effect on the change of the topological structure of glass. It can be concluded that the main reason for the change of physical properties of glass is the difference of the strength between chemical bonds in the glass structural system.

A thorough investigation of the Bi2O3–PbCl2–TeO2 system: Glass forming region, thermal, physical, optical, structural, mechanical and radiation shielding properties

In the present work, a series of glasses in the Bi2O3–PbCl2–TeO2 system are synthesized by conventional melt quenching technique. Glass forming region of the specially designed glass system is determined. Thermal properties of glasses – glass transition (Tg) and crystallization (Tc/Tp) temperatures and glass stability against crystallization (∆T) – are determined. Density and refractive index values are measured to interpret various physical properties of glasses. Optical and structural properties are studied through visible transmittance and Fourier transform infrared spectroscopy analysis. Mechanical properties are investigated by Vickers hardness measurements. The radiation shielding competence of glasses is evaluated in the energy range from 0.161 MeV to 2.51 MeV using Phy-X/PSD simulation program. The mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), effective atomic number (Zeff), half value layer (HVL), tenth value layer (TVL) and mean free path (MFP) are calculated. Glasses in the Bi2O3–PbCl2–TeO2 system possess superior shielding effectiveness than other commercially available radiation shielding glasses owing to higher MAC and lower HVL and MFP values.

A study of NIR emission and associated spectroscopic properties of Nd3+:P2O5+K2O+Al2O3+ZnF2 glasses for 1.06 μm laser applications

For studying spectroscopic properties of 1.06 μm laser emission, zincfluorophosphate glasses(PKAZf) with varying of Nd2O3 concentration were fabricated by the melt-quenching technique. Amorphous nature, thermal stability and physical properties of glasses were studied in detail. The optical band gap of PKAZfNd1.0 glass was estimated for indirect(3.21 eV) and direct(3.34 eV) transitions. The radiative parameters like radiative emission probability, radiative lifetime, branching ratio, and effective line width were calculated for 4F3/2→4I13/2,11/2,9/2 transitions. With 808 nm irradiation, the NIR emission spectra showed a strong band at 1.06 μm (4F3/2→4I11/2), and two less intensity bands at 1.33 μm (4F3/2→4I13/2) and 0.89 μm (4F3/2→4I9/2). The decay curves were fitted to the double exponential function and the decrease of lifetimes from 261 to 208 μs was observed. The PKAZfNd1.0 glass provides some favorable spectroscopic parameters: high gain (125.61 × 10−25 cm2s) and low threshold (1.67 × 108 W/m2) properties, including stimulated emission cross-section (4.74 × 10−20 cm2) and quantum efficiency (89%).

Thin Glass Handling Solutions for Microelectronics Packaging

Abstract Glass substrates with fine-pitch through-glass via (TGV) technology gives an attractive approach to wafer level packaging and systems integration. Glass can be made in very thin sheets (<100 um thick) which aids in integration and eliminates the need for back-grinding operations. Electrical and physical properties of glass have many attractive attributes such as low RF loss, the ability to adjust thermal expansion properties, and low roughness with excellent flatness to achieve fine L/S. Furthermore, glass can be fabricated in panel format to reduce manufacturing costs. The biggest challenge to adopting glass as a packaging substrate has been the existence of gaps in the supply chain, caused primarily by the difficulty in handling large, thin glass substrates using standard automation and processing equipment. This paper presents a temporary bonding technology that allows the thin glass substrates to be processed in a semiconductor fab environment without the need to modify existing equipment.

Comparative investigation on the structure and physical properties of CeO2/TiO2/Sb2O3-doped bismuth borosilicate glasses

Glasses with composition of 30Bi2O3-15B2O3-40SiO2-15ZnO doped with CeO2, TiO2 or Sb2O3 were synthesized by melt-quench and were characterized in structure and properties. The results show that dopants allows conversion of [BO3] to [BO4] and facilitates the formation of [BiO3]/[BiO6] units and that glass physical properties are jointly influenced by the dopants-induced network alteration, bond strength and atomic compactness. Thermodynamic calculation combined with reaction kinetics analysis indicate that the varied oxygen bonding affinity of metal oxides as well as their susceptibility to melting temperature significantly affect the valence state of yielded metallic ions species that contribute to energy level transitions of electrons strongly associated with transmittance of the glasses. Oxides with lower oxygen bonding affinity may facilitate the oxidation of those with relatively higher oxygen bonding affinity. Thermodynamic and reaction kinetics methods can thus be used as the semiquantitative tools for optimizing glass synthesis process with tailored optical properties.

Thermal history and its implications: A case study for ion exchange

AbstractGlasses containing monovalent species can be chemically strengthened by the replacement of smaller ions in the glass with larger external ions in the near glass surface. This type of ion exchange puts glass surface under high compressive stress (CS). Glass mainly fails from tension with the presence of surface flaws. Chemical strengthening can change the stress at the flaw tip from tension to compression and further stop the flaw from propagating. Glass damage resistance is therefore significantly improved. For the same glass composition, glass thermal histories can affect the magnitude and depth of the CS generated during ion exchange. In this study, the impact of thermal history on glass physical properties and ion exchange attributes in one alkali‐containing glass formed by fusion draw process was investigated. Multiple thermal treatments were done to rewrite the glass thermal histories. Glass density, refractive index, and ion‐exchange properties as a function of the thermal treatment were studied. It is concluded that ion exchange‐related properties change dramatically with the glass thermal history.

Influence of Glass and Air on Our Perception of DNA

The chemical and physical properties of glass do not allow it to be considered as an inert material. Therefore, it is necessary to discuss the ability of laboratory glassware to influence the state and properties of aqueous solutions, including DNA solutions. As a demonstration of this ability, it is shown here how contact with glass affects the state of salts in aqueous solutions. In terms of the topic under discussion, it is especially important that sodium salts are very sensitive to these contacts. Thus, it is shown here that contact with glass can affect the formation of fibers from sodium salts of DNA, which were mainly used in X-ray studies aimed at determining the molecular structure and parameters of DNA molecules. Special attention is paid to the fact that laboratory glassware is also sensitive to contact with aqueous solutions, including DNA solutions. That such sensitivity may be important to biologists is also shown here. In particular, it was shown how ignoring the sensitivity of silica glass, from which the photometric cells are made, to electrization gave rise to misconceptions about the spectral properties of aqueous solutions, including DNA solutions. The effect of air dissolved in aqueous DNA solutions on the spectral properties of both these solutions and the photometric cells containing them is also shown. In particular, it was shown that UV absorption of aqueous DNA solutions, which does not contain air, is completely insensitive to heating, and UV absorption of aqueous DNA solutions, which are saturated with air, is supersensitive to heating. In other words, it is shown here that our understanding of the thermal denaturation of DNA, which is reflected in the UV absorption of its aqueous solutions, was formed due to these two types of sensitivity. In the end, a conclusion is proposed here about the significant contribution of glass and air to the creation of traditional ideas about the structure and properties of DNA.

Iodine solubility and speciation in glasses

The study of iodine in glasses and melts is critical in many areas, from geosciences to materials science to waste management. Glasses in the ternary system Na2O-B2O3-SiO2 were studied with the goal of identifying a glass matrix able to dissolve large quantities of this element, and to identify the main parameters affecting the solubility of iodine. Two sets of experiments were carried out: the first one with the aim of determining the solubility limit of iodine, and the second one to identify the structural variations occurring within the glass network upon iodine incorporation, and to identify the parameters influencing the most both iodine solubility and speciation. We demonstrated that there is a strong dependence of iodine incorporation on bulk chemistry and glass physical properties. A solubility limit of ~5 mol% I has been assessed for B2O3-rich glasses and of ~1 mol% for SiO2-rich ones, and this composition dependence has been explained by considering the fragility parameter of the glass network. Structural variations in the iodine local environment and in the glass network were characterized by Raman, X-ray Absorption Spectroscopy, and 11B NMR. Spectroscopy data point out the coexistence of different I species within the glasses, with iodide being the predominant one, surrounded by Na+ ions.

Formation and optical properties of new glasses within Sb2O3–WO3–ZnO ternary system

New Sb2O3-based heavy metal oxide glasses in the Sb2O3–WO3–ZnO ternary system were prepared using a conventional melt-quenching method. The glass-forming domain and physical properties like density, thermal, structural and linear optical properties of the glasses have been investigated. The physical properties of glasses have been studied extensively as a function of WO3 and ZnO concentration (mol%) in the Sb2O3–WO3–ZnO ternary glassy system. It was found that the glass transition temperature increases linearly with WO3 concentration, but thermal stability decreases, while both the glass transition temperature and thermal stability almost linearly increases with ZnO concentration. The glasses within 60Sb2O3–xWO3–(40 − x)ZnO ternary system with x = 10, 15 and 20 were found as most thermally stable glasses. The density and refractive index of these glasses increases as the content of WO3 increases. The available free space in the glass i.e. free volume and optical band gap of the glass decreases with higher concentration of WO3. This work demonstrates that proper composition can lead to effective and beneficial change in physical properties of the Sb2O3-based glasses.

Local structure, connectivity and physical properties of glasses in the B2O3-Bi2O3-La2O3-WO3 system

Glasses of (100 - (x + y))·(0.6B2O3·0.4Bi2O3)·xLa2O3·yWO3, x = 0, 10; y = 0 ÷ 40 mol% were prepared by melt quenching. Density measurements, thermal analysis, UV–vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy and theoretical modeling using Density Functional Theory were employed to identify the effect of WO3 content on the structural and physicochemical properties of these glasses. The glass transition temperature and density increase steadily with increasing WO3 content, most probably because of the formation of mixed Bi–O–W and La–O–W crosslinks. The lower band gap energy values show that the introduction of WO3 or La2O3 to 60B2O3·40Bi2O3 glass increases the number of non-bridging oxygen species in the glass structure. The photoelectron analysis aided by theoretical calculations discover that additionally to the tetrahedrally coordinated W ions, most of the existing WO6 octahedral units in glasses with nominal WO3 content below 20 mol% are distorted, leaving practically the tungsten ions in a quasi-tetrahedral coordination. At higher WO3 content (30–40 mol%) the concentration of octahedrally coordinated tungsten atoms dominate strongly over those of tetra- and quasi-tetra-coordinated W ions. Moreover, the comparison with appropriate crystal standards allows offering a complete description of the existing bridging and non-bridging linkages and their most likely O1s binding energies.

The Polarizability and Optical Characteristics of Zinc Phosphate Glasses Doped Terbium Embedded with Copper Oxide Nanoparticles

Tuning the concentration of nanoparticles (NPs) to accommodate wider application demanded a better understanding of the physicals and structural properties of the glass. A series of zinc phosphate glasses with the composition of (57-x) P2O5- 40ZnO-3Tb2O3 –xCuO, (0 ≤ x ≤ 2 mol %) has been prepared by melt quenching technique and their physical and optical characterization have been studied. The X-Ray Diffraction technique and UV-Vis Spectroscopy have been used to characterize the glass sample. The XRD confirms the amorphous nature of the prepared glasses. The physical properties of glasses with different CuO NPs such as density, molar volume, refractive index and electronic polarizability are determined. It is found that both density and molar volume decreases with increasing CuO NPs concentration. The optical band gap (4.54 eV-2.96 eV) and the Urbach energy (0.19 eV-0.54 eV) are showing a decreasing trend with the increasing amount of CuO NPs.This is due to the formation of non-bridging oxygen, (NBO) in the glass network. The glass exhibits high refractive index ~2.40 and polarizability ~1.12 ×10-23 cm3 and is useful for solid-state laser and optoelectronic devices.

Physical properties and structural studies of lithium borophosphate glasses containing TeO2

This work presents a study on the structure, thermal behavior and properties of (100-x)[0.5Li2O-0.1B2O3-0.4P2O5]-xTeO2 glasses prepared within the concentration range of x = 0–80 mol% TeO2. The structure of the glasses was studied with a combined Raman, 31P and 11B MAS NMR spectroscopy. 31P MAS NMR and Raman spectrum of the pure 50Li2O-10B2O3-40P2O5 glass indicates the co-existence of Q2 and Q1 phosphate units in the glass structure. Raman spectra of TeO2 containing glasses revealed that TeO2 is incorporated in the structural network in the form of TeO3 and TeO4 (TeO3+1) units. The ratio of TeO4/TeO3 increases with rising TeO2 content. Apart from the formation of P‒O‒Te and Te‒O‒Te bonds, the formation of B‒O‒Te bonds in the form of mixed tetrahedral units B(OP)4-n(OTe)n also takes place as shown by 11B MAS NMR spectroscopy. The structural studies were correlated with the thermal behavior and physical properties of glasses (density, molar volume, chemical durability and refractive index). DSC studies showed that all glasses crystallize on heating within a temperature region of 400–550 °C and the surface nucleation mechanism prevails over the internal one. The crystallization temperature decreases with increasing TeO2 content. The compounds formed by crystallization were LiPO3, Li4P2O7, BPO4 and α-TeO2. Glass transition temperature and dilatometric softening temperature, estimated from thermodilatometry curves, decrease with increasing TeO2 content, whereas the thermal expansion coefficient increases.

Composition – structure – property relationships in alkali aluminosilicate glasses: A combined experimental – computational approach towards designing functional glasses

A set of 12 glass compositions with distinct structural features have been designed over a broad composition space in the per-alkaline region of the Na2O – Al2O3 – SiO2 ternary system. As expected from a per-alkaline system, aluminum has been found to be tetrahedrally coordinated in all the glasses using 27Al magic angle spinning – nuclear magnetic resonance (MAS-NMR) spectroscopy and from structure models generated using molecular dynamic (MD) simulations. The physical properties of glasses, for example, density, coefficient of thermal expansion (CTE), glass transition, elastic moduli and Vickers hardness and brittleness have been measured experimentally and their trends have been explained based on the atomic structure of glasses, from both simulations and experiments. A reasonable agreement has been observed between the composition – structure – property relationship trends obtained experimentally when compared with those predicted by MD simulations. This demonstrates that MD simulation is a promising technique for predictive modeling and designing novel glass compositions for functional applications.

Thermo-optical and structural properties of barium aluminoborate glasses

In this work, we have prepared 22 barium aluminoborate glass compositions and investigated their thermo-optical and structural properties. The non-hygroscopic glass composition (71−x) B2O3:(20+x) BaO:9 Al2O3 with x = 0, 5, 10, 15, and 20 (%mol) presented high transparency in the visible to near-infrared region of about 80%. X-ray diffraction patterns have shown no crystalline phase and indicated a structural change feature. As BaO content increases from 20 to 40 mol%, the density increased from 2.82 to 3.696 g/cm3 whereas Vickers hardness decrease from HV = 5.3 to 4.2 GPa. The FTIR curves indicate three main regions concerning BOB, BO4, and BO3 units. Refractive index measured at 546 nm varied from 1.5611 to 1.6371, whereas dn/dT remained almost constant i.e. 1.69×10−5°C−1. Thermal Diffusivity obtained by thermal lens technique indicated a decreased from 3.4 to 2.8 cm2×10−3/s as BaO is added to the glass compositions. The results indicate that non-bridging oxygen plays an important effect on glass physical properties.

The effect of Sn on the physical and optical properties of (Se0.6As0.1Ge0.3)100-xSnx glasses

Chalcogenide glasses are significant materials for semiconducting and infrared imaging because of their infrared (IR) transparency. In the present study, Se-Ge-As based chalcogenide glasses with chemical composition of (Se0.6As0.1Ge0.3)100-x Snx doped with different amounts of Sn were prepared by conventional melting-quenching method. Physical properties of glasses were investigated by studying density and molar volume. Based on differential scanning calorimetry (DSC) results and density measurements, the binary role of Sn was proved. Fourier transform infrared spectroscopy (FT-IR) study of the samples approved presence of impurities. Using the UV–Vis spectra, optical properties including Fermi energy level, direct and indirect optical band gap and Urbach energy were determined. The results showed a decrease in density of glasses with the increase of Sn from 2 to 6 mol%. Increasing Sn in the glassy microstructure of samples provides a semiconducting character to Se based chalcogenide glass by reducing the direct and indirect optical band gaps of glass samples from 1.29 to 1.15 (eV) and 1.16 to 1.01 (eV), respectively.