Doped Soda-lime Silicate Glasses Research Articles

Viscosity of alumina doped soda lime silicate glasses – observation of anomaly in the linear increase as Al2O3 replaces SiO2

Adding alumina to the conventional soda lime silicate glass composition improves many properties, however, also increases the melting temperature. In the current paper, alumina doping of soda lime silicate glasses and its implications to high temperature viscosity are investigated in order to verify the linearity when replacing SiO2 for Al2O3. An anomaly in the linearly increasing viscosity was found when the ratio CaO/Al2O3 is <1, which is explained by Ca2+ acting as an inhibitor for viscous flow. The Angell and Rao and the Waterton-MYEGA models show very similar results, even for the extrapolated Tg. Thermodynamic data extracted using the Ojovan method generally increases linearly with the Al2O3 content. The Doremus fragility index shows a deviation in the linearity while the Angell fragility index on the other hand shows a linear increase with the Al2O3 content.

Roman glasses coloured by dissolved transition metal ions: redox-reactions, optical spectroscopy and ligand field theory

A collection of Roman glass samples from Ancient Messene, Greece, was analysed non-destructively for colouring elements and non-colouring additives such as fining agents, opacifiers and decolourizers, by comparing the chemical composition with the observed optical spectra. The resulting information on ion speciation is important for the discussion of technological parameters such as the applied melting temperatures or the prevalent redox conditions. Speciation also helps to distinguish intentionally added dopants from impurities. This knowledge might be used in provenancing the raw materials. The Roman assemblage under study included purple coloured Mn3+-containing glasses, but also samples with high levels of colourless Mn2+. Manganese ions can either be considered a residue of recycling, or are indicative of an intentional addition, either as a fining or as a decolouring agent. Antimony oxide was either added as a fining agent, resulting in good quality transparent glasses, or as crystalline antimonates which act in glass mosaic tesserae as opacifiers. The much weaker molar extinction coefficient and the partial reduction of blue Cu2+ to colourless Cu+ explain why CuO is a weaker colouring agent than CoO. The colours of iron-bearing glasses range from light blue to green and from yellow to dark brown, reflecting a complex interplay between redox conditions and the presence of sulphur in the glass melt.Quantitative speciation of dopants will be reviewed on the basis of the ligand field theory. The different transition probabilities will be demonstrated on differently doped soda lime silicate glasses which were prepared for this purpose in the laboratory.

ER&lt;sup&gt;3+&lt;/sup&gt;-DOPED SODA-LIME SILICATE GLASS: ARTIFICIAL PINK GEMSTONE

Er3+-doped soda-lime silicate glasses of the composition (in mol%) (65-x)SiO2:25Na2O:10CaO:xEr2O3 (where x = 0, 1, 2, 3, 4 and 5) were fabricated by conventional melt quenching technique. The physical and optical properties were measured and investigated. The erbium oxide enters the glass network as a modifier by occupying the interstitial space in the network and generating the NBOs to the structure. The molar volume increases with an increase in Er2O3 content, which is attributed to the increase in the number of Non-Bridging Oxygen (NBOs). The increase of NBOs in the structure generally leads to an increase in average atomic separation. The density, molar volume and refractive index of glasses increased linearly with increasing Er2O3 concentration. The color of glasses was changed from light pink to intense pink as the Er2O3 concentration was increased from 1 to 5 mol%. The Vickers hardness of Er3+-doped glasses was found to be in the range of 450-500 HV. In this study, it can be concluded that the soda-lime silicate glasses doped with high Er2O3 concentration has intense pink color and high value of hardness which is suitable to be cut as gems.

Optical and electronic polarizability investigation of Nd 3+-doped soda-lime silicate glasses

This paper reports on different physical and optical properties of Nd 3+-doped soda-lime silicate glass. The glasses containing Nd 3+ in (65− x)SiO 2:25Na 2O:10CaO: xNd 2O 3 (where x=0.0–5.0 mol%) have been prepared by the melt-quenching method. In order to understand the role of Nd 2O 3 in these glasses the density, molar volume, refractive index and optical absorption were investigated. The results show that the density and molar volume of the glasses increase with an increase in Nd 2O 3 concentration and consequently generate more non-bridging oxygen (NBOs) into glass matrix. The optical absorption spectra were measured in the wavelength range from 300 to 700 nm and the optical band gaps were determined. It was found that the optical band gap decreases with an increase in Nd 2O 3 concentration. On the basis of the measured values of density and refractive index, the Nd 3+ ion concentration in glasses, the polarizability of oxide ions and optical basicity were theoretically determined.

Optical Investigation and Electronic Polarizability of Nd3+ Doped Soda-Lime-Silicate Glasses

Problem statement: This study researched on different physical and optical properties of Nd3+ doped soda-lime-silicate glass. The glasses containing Nd3+ in (65-x)SiO2: 25Na2O: 10CaO: xNd2O3 (where x = 0.0-5.0 mol%) had been prepared by melt-quenching method. The density and molar volume increase with increasing of Nd2O3 concentration due to increasing of Non Bridging Oxygen (NBOs) in glass matrix. The optical spectra were measured and evaluated their optical band gap and found to decrease with increasing of Nd2O3 concentration. Moreover, these results showed that the refractive index of glass does not only depend on the density but also depend on the electronic polarizability of the glass. The values of polarizability of oxide ions, theoretical optical basicity were also determined. Approach: This study investigated the effect of Nd2O3 content on optical band gap, density, molar volume, optical basicity and polarizability in soda-lime silicate glass. Series of Nd3+ doped soda-lime silicate glasses (in mol%): (65-x)SiO2-25Na2O-10CaO-xNd2O3 (x = 1-5 mol%) were prepared by the normal melt-quenching technique. Analytical reagent grade chemicals of SiO2, Na2O, CaO and Nd2O3 were used in the glasses preparation. Each batch of chemical was powdered finely and mixed thoroughly in porcelain crucibles and was later melted in an electrical muffle furnace for 3 h, at 1200°C. After complete melting, the homogenized melt was quickly poured onto a stainless steel mould that was heated at 500°C to form the glasses. The glass blocks thus resulted were immediately transferred to the annealing furnace that and were annealed at 500°C for 3 h and then slowly cooled down to the room temperature in order to remove possible thermal stains in the glasses. Finally, the as-prepared glass samples were cut and then finely polished to a thickness of 3 mm. The glass densities were measured by using xylene as an immersion liquid based on the Archimedes's principle. Glass refractive indices were measured at room temperature using an Abbe refractometer (ATAGO) and mono-bromonaphthalene as an adhesive coating. The optical absorption spectra of Nd3+ doped soda-lime silicate glasses were recorded at room temperature using a UV-VIS spectrophotometer (Hitachi, U-1800), working in 300-700 nm. Results: By addition of Nd2O3 into the SiO2-Na2O-CaO glass network, the density increases with increase in Nd2O3 content. The molar volume of the glass systems under study increases with increase in Nd2O3 content, which is attributed to increase in the number of Non Bridging Oxygen (NBOs). The optical band gap slightly decreases with the increase of Nd2O3 and results in the increase of bonding defect and non-bridging oxygen. The optical basicity of the glasses are increasing with Nd2O3 content change with the increasing of polarizability and consequently the increase in refractive index. Conclusion: The study of SiO2-Na2O-10CaO-Nd2O3 glass systems showed that the density and refractive index increase with increasing concentration of Nd2O3. The increase of molar volume with Nd2O3 content indicates that the extension of glass network is due to the increase of the number of NBOs. The optical band gap slightly decreases with in Nd2O3 content due to an increase in the degree of localization of electrons thereby increase of the donor center in the glass matrix. The electronic polarizability and optical basicity increase with the increase of mol% of Nd2O3, which is in agreement with the decrease of optical band gap. Moreover, the results found in this study show that the refractive index of glass does not only depend on the density but also depend on the electronic polarizability of the glass.

Spectroscopic investigations and luminescence spectra of Sm 3+ doped soda lime silicate glasses

Sm 3+ doped soda lime silicate glasses co-doped with As 2O 3 were prepared and characterised by measuring their absorption spectra in UV-VIS/NIR regions and luminescence spectra in the visible region. Judd-Ofelt intensity parameters, Ω λ, were evaluated from the measured intensities of the various absorption bands. Ω λ parameters of these glasses were compared with the Ω λ parameters of other reported Sm 3+ glasses to study the bonding environment surrounding the Sm 3+ in the present glasses. Presence of [AsO 4] 3– tetrahedra in the second coordination sphere around the central Sm 3+ ion made these glasses less covalent as compared to other oxide glasses but the ratio Ω 4/ Ω 6 of the ∼1.83 indicated them to be fairly stable. With the help of Ω λ parameters and luminescence data for various emission lines, radiative properties for different emission lines were calculated. The values of radiative properties indicated that 4G 5/2→ 6H 7/2 and 4G 5/2→ 6H 9/2 transitions responsible for orange luminescence might be used in the development of materials for LED's and other optical devices in the visible region.

Influence of Al2O3 addition on thermal and structural properties of erbium doped glasses

Changes in the structural properties of Er3+ doped soda-lime silicate glasses were investigated as a function of Al2O3 content. A combined approach of experimental techniques and molecular dynamic simulations (MD) was used to evaluate the structural features directly correlated to the glass properties. The experimental results in term of density, thermal properties as well as microstructural and mineralogical data showed a significant variation when increasing the alumina content from 10 mol% to 15 mol%. These results were compared to the MD information and discussed: changes in erbium and aluminium local configuration, due to the glass structural evolution as a function of the alumina concentration, have been investigated.

Spectral studies of erbium doped soda lime silicate glasses in visible and near infrared regions

Optical absorption and photoluminescence spectra of Er 3+ doped soda lime silicate glasses of the composition (in wt.%) 68.94SiO 2–22.55Na 2O–1.91CaO–4.96K 2O–0.85B 2O 3–0.29As 2O 3– xEr 2O 3 where x = 0.0, 0.2, 0.3 and 0.5 have been studied in the UV–VIS/NIR regions. From the measured intensities of the various absorption bands of these glasses, the Judd–Ofelt parameters Ω 2, Ω 4 and Ω 6 have been evaluated. Judd–Ofelt theory has been successfully applied to characterize the absorption and luminescence spectra of these glasses. From this theory various radiative properties like spontaneous emission probability, radiative life time, fluorescence branching ratio and stimulated emission cross-section for various emission bands of these glasses in the visible and NIR spectral regions have been determined and reported. An attempt has been made to through some light on the environment of Er 3+ in this glass system. Radiative properties of fluorescence band at ∼1.54 μm suggest the suitability of this glass system for broadband amplifier in the third telecom window.

Structural and electrical characteristics of copper doped soda lime silicate glasses

Commercially available soda lime silicate glasses (SLSG), with composition corresponding to the miscibility range, were studied to characterise their electrical properties, and to determine the dependence of these characteristics on the glass microstructure. Sodium ions, present in the glass matrix, were partially substituted by copper ions, and after the ion exchange process the specimens were annealed in a hydrogen atmosphere. It has been stated that besides the formation of copper and copper oxide nanoparticles, the joint effect of chemical and thermal treatment results in partial transformation of the Na2O-rich droplets, present in as prepared specimens, into interconnected structures, their re-dispersion and secondary phase separation. These phenomena are responsible for the behaviour of thermally stimulated depolarisation current (TSDC) spectra measured for the copper-doped SLS glasses. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Influence of annealing on optical properties of cerium doped soda-lime–silicate glasses

Effects of annealing on optical absorption (OA) and photoluminescence (PL), emission and excitation spectra from a cerium doped soda-lime–silicate glass ion-exchanged with silver were investigated. Annealing experiments were performed at temperatures of 350 and 400°C, far below the 569°C transition temperature measured for the doped glass. Evidence of surface-plasmon resonance of metallic silver nanoparticles and its subsequent disappearance in the OA spectra by annealing effects are reported. In this case, the reduction of Ag + to elemental silver and further reoxidation are governed in part by the reaction Ce 3++Ag +↔Ce 4++Ag 0. Results are in agreement with a preferential formation of silver nanoparticles at the surface, where the strain energy is more easily relaxed. On the other hand, PL spectra are also affected by the annealing, principally excitation spectra. Analyses of these spectra by de-convolution into three Gaussian shapes were carried out. The influence of annealing has a special significance for the excitation component centered between 3.94 and 3.84 eV (∼315 and 323 nm), related to Ce 3+ centers. Superficial increase in the number of Ce 4+ partially prevents excitation of remaining Ce 3+ ions and, therefore, enhances self-absorption in the glass. The main changes in the OA and PL spectral features are discussed in terms of the reducing role of Ce 3+ ions and on the basis of thermal relaxation of the surface tensile stress caused by differences in size between Ag + and Na + ions.

Active optical waveguides based on Er- and Er/Yb-doped silicate glasses

The growing interest for the use of integrated optical (IO) amplifiers in optical fibre telecom systems has led to depth search for ever better rare-earth-doped glassy materials. In the present paper we report some properties of a set of Er 3+/Yb 3+-doped soda-lime silicate glasses. Several batches were prepared, all with the same base mol% composition (73SiO 2–1Al 2O 3–0.4P 2O 5–14Na 2O–0.6K 2O–11CaO) containing Er 2O 3 (0.32–0.48%) and Yb 2O 3 (0.63 and 0.78%). The resulting glasses were cut into rectangular plates about 1 mm thick, and one surface was optically polished. Planar and channel waveguides were subsequently obtained in these plates by Ag +–Na + ion-exchange. Spectroscopic analysis showed that the fluorescence emission peak for all the samples was observed at 1532±1 nm, with a full-width at half-maximum equal to 19 nm. Measurements of the lifetime of the metastable state of Er 3+ were performed upon excitation by laser pumps at 514.5 and 980 nm, and times of the order of 7 ms were measured in most samples. The intensity of the up-conversion fluorescence was less in Er 3+/Yb 3+ co-doped glasses than in Er 3+-doped ones. Preliminary measurements of the transmitted power at 1540 nm in channel waveguides made in the glass doped with nominal 0.32 mol% of Er 2O 3 have confirmed their potential of achieving optical gain; in fact, a signal enhancement (internal gain) >1 dB/cm was measured with more than 1 mW input signal.