TeO2 Glasses Research Articles

Physical and optical properties of Sb2O3 B2O3 Bi2O3 TeO2 glass system

Physical and optical properties of Sb2O3 B2O3 Bi2O3 TeO2 glass system

Shielding of beta and bremsstrahlung radiation with transparent Bi2O3-B2O3-TeO2 glasses in therapeutic nuclear medicine

High-energy beta emitters (yttrium-90, strontium-89 and phosphorus-32) are nowadays increasingly used in therapeutic nuclear medicine. Beta particles and bremsstrahlung (photons produced when beta particles interact with materials) are harmful and should be shielded in order to protect the personnel and public from their harmful effects. This work determined the radiation yield, effective atomic number and range associated with the interaction of beta particles with a transparent xBi2O3-30B2O3-(70-x)TeO2 glass system (where x = 40, 50, 60 and 70 mol%) using the ESTAR database and programme; and other relevant equations. The properties of the studied glass systems were compared with transparent lead glass, which is unwanted in the medical settings because of lead’s toxicity. The result of this work showed that the studied glasses are suitable for use in making vials, syringes and other transparent materials, necessary for shielding high-energy beta particles. All the studied glass systems can replace lead glass.

Physical and properties of Nb2O5 BaO TeO2 glass system with compositional variations

The density calculated decreases with increase of Nb2O5 content from 5.680 g cm-3 to 5.493 g cm-3, this means that , the glass matrix becomes less dense, It was found that , the optical energy gap decrease, but the refractive index increase by increasing Nb2O5 content . The electronic polarizability of oxide ion decrease with decreasing the optical basicity. The value of optical basicity shows that the glass materials are less basic. It is suggested that by increasing Nb2O5 content , the glasses become less polarized. Also, It was found that the values of third order nonlinear susceptibility increase by increasing Nb2O5 content and are found to be larger than those of the silica based glasses. The glasses are found to possess a high refractive index (2.170 – 2.213), a comparatively narrow band gap (3.992 eV – 3.785 eV), high electronic ion polarizability (2.445 A3 -2.546 A3) and high optical basicity (0.987 – 1.014). It was found that the values of the third order nonlinear optical susceptibility are in the range (0.7604-0.9271)x10-12 esu. Finally, all the above values are a good basis for predicting new non linear optical materials.

Investigation of radiation shielding properties for Bi2O3 - V2O5 - TeO2 glass system using MCNP5 code

In materials engineering design understanding and prediction over the physical properties are essential to develop new class of functionalized materials. The objective of this work is to assess the radiation shielding properties for Bi2O3 - V2O5 - TeO2 glass system. For this aim, the MCNP5 Monte Carlo code was used to estimate the mass attenuation coefficients (μ/ρ) for the Bi2O3 - V2O5 - TeO2 glasses in the energy range of 0.356-1.33 MeV. The MCNP5 values of μ/ρwere verified by XCOM at the selected energy range.The results showed that BiVTe6 and BiVTe1 glass samples have the highest and lowest values of mass attenuation coefficient respectively. The addition of Bi2O3 in the glass samples leads to a reduce in HVL and MFP values at all photon energies. Hence, BiVTe6 glass sample possesses the lowest HVL and MFP values, thus this glass sample has better shielding properties in comparison with the other samples in this work.The exploitation of their useful shielding properties may open many new technological applications in optoelectronics and radiation protection.

Short-range structure of barium tellurite glasses and its correlation with stress-optic response

The atomic parameters of metal ion-oxygen speciation such as bond-lengths and nearest neighbor distances for Ba-O, Te-O and O-O pairs, co-ordination numbers and bond angle distributions for O-Ba-O, O-Te-O and O-O-O linkages are determined by neutron diffraction and Reverse Monte Carlo simulations on the series of xBaO-(100-x)TeO2 glasses containing 10, 15 and 20 mol% BaO. The glass network depolymerizes and the average Te-O co-ordination number decreases from 3.60 ± 0.02 to 3.48 ± 0.02 with increase in BaO concentration. Te-O bond lengths are in the range: 1.97 ± 0.01–1.92 ± 0.01 Å. Ba2+ is mostly in octahedral coordination and the Ba-O bond lengths are in the range: 2.73 ± 0.01 to 2.76 ± 0.03 Å. Te-O co-ordination number is also determined by Raman spectroscopy and it shows good agreement with the neutron data. The short-range structural properties i.e. metal ion coordination number (Nc) and bond lengths (d) were correlated with the stress-optic response. The bonding characteristic, Br values were determined from the structural data of xBaO-(100-x)TeO2 glasses and were used to predict the stress-induced birefringence properties.

Third order nonlinear optical properties of a paratellurite single crystal

The (a,b) plane angular dependence of the third-order nonlinear optical susceptibility, χ(3), of a c-cut paratellurite (α-TeO2) single crystal was quantitatively evaluated here by the Z-scan technique, using a Ti:sapphire femtosecond laser operated at 800 nm. In particular, the mean value Re(⟨χ(3)⟩a,b)(α-TeO2) of the optical tensor has been extracted from such experiments via a direct comparison with the data collected for a fused silica reference glass plate. A Re(⟨χ(3)⟩(a,b)(α−TeO2)):Re(χ(3))(SiO2 glass) ratio roughly equal to 49.1 is found, and our result compares thus very favourably with the unique experimental value (a ratio of ∼50) reported by Kim et al. [J. Am. Ceram. Soc. 76, 2486 (1993)] for a pure TeO2 glass. In addition, it is shown that the angular dependence of the phase modulation within the (a,b) plane can be fully understood in the light of the strong dextro-rotatory power known for TeO2 materials. Taking into account the optical activity, some analytical model serving to estimate the diagonal and non-diagonal components of the third order nonlinear susceptibility tensor has been thus developed. Finally, Re(χxxxx(3)) and Re(χxxyy(3)) values of 95.1×10−22 m2/V2 and 42.0×10−22 m2/V2, respectively, are then deduced for a paratellurite single crystal, considering fused silica as a reference.

Investigating the influence of transition metal oxides on temperature dependent optical properties of PbCl2–TeO2 glasses for their evaluation as transparent large band gap semiconductors

A series of ternary glasses in the MeO–PbCl2–TeO2 (MeO = Bi2O3, MoO3, Sb2O3, WO3, ZnO) system have been synthesized by conventional melt quenching technique. Thermal properties of glasses – glass transition (Tg) and crystallization (Tc/Tp) temperatures, temperature difference (ΔT) and thermal stability (S) values – were determined using differential scanning calorimetry. The influence of transition metal oxides on refractive index, position and shift rate of absorption edge, optical band gap energy (Eopt) and Urbach energy (ΔE) was investigated and their dependence on temperature was studied. The Eopt and ΔE values of all glasses studied in this work were found to be comparable with the values corresponding to some semiconductors. The glasses under study show great potential for applications in optoelectronics.

Optical and dielectric properties of the SiO2–B2O3–Bi2O3–TeO2 glass system

Optical and dielectric properties of the SiO2–B2O3–Bi2O3–TeO2 glass system

Photon shielding characterizations of bismuth modified borate –silicate–tellurite glasses using MCNPX Monte Carlo code

In this study, the radiation mass attenuation coefficients of different bismuth-borate glass samples as shielding materials are calculated at 356, 662, 1173 and 1332 keV photon energies by using general purpose Monte Carlo code MCNPX (version 2.4.0). The obtained numerical results agreed well with previous experimental, theoretical results and with standard XCOM data. The validated simulation geometry has been used then to investigate the photon attenuation properties of B2O3–Bi2O3–SiO2–TeO2 glass system. The photon shielding parameters such as mass attenuation coefficients, effective atomic number, and mean free path have been calculated and the variation in these parameters was discussed in terms of both photon energy and Bi2O3 concentration. The maximum values of mass attenuation coefficients and effective atomic number were found for Bbi7 glass sample. The photon shielding properties for the B2O3–Bi2O3–SiO2–TeO2 glasses have been compared in terms of half value layer with some commercially-available shielding glasses developed by SCHOTT company. Also, the mean free path for the present glasses have been compared with those of different glass samples and steel-magnetite concrete. The comparison reveals that the B2O3–Bi2O3–SiO2–TeO2 glass system can be used for photon shielding applications.

Short-Range Structure of TeO2 Glass

The short-range structure of TeO2 glass was studied by a combined solid-state NMR, Raman, and first-principles calculation approach. Glass samples enriched in oxygen-17 were prepared, and both 125Te and 17O spectra were recorded. In addition, spectra of α-TeO2 and γ-TeO2 crystal phases were recorded to aid in spectral assignment. The identity of the crystal phases was confirmed by X-ray diffraction and Raman spectroscopy. First-principles computations on the TeO2 crystal phases as well as on several potassium tellurites were carried out for comparison. It was found that the structure of TeO2 glass is best described as a highly disordered form of the γ-TeO2 crystal.

EPR, optical and physical studies on Cr3+ doped MgO–BaO–B2O3–TeO2 glasses

Physical, optical and Electron Paramagnetic Resonance (EPR) studies on 15MgO–15BaO–(59.8−x) B2O3–(10 + x) TeO2–0.2Cr2O3 (x = 0,10,20,30 mol%) glass samples are reported. EPR spectra exhibited two resonance signals at g = 4.8 and g = 1.98. The resonance signal with large zero field splitting parameter (D) and E/D ≤ 1/3 at g = 4.8 is attributed to isolated Cr3+ centers in strongly distorted octahedral sites, whereas the resonance signal at g = 1.98 is assigned to Cr3+ centers at axially distorted octahedral sites. The resonance signal at g = 4.26 is assigned to Fe3+ ions, which are present in the glass matrix as unwanted impurities. The resonance signal at g = 1.91 indicates the Cr3+–Cr3+ exchange coupled pairs. The two observed broad optical bands in the optical absorption spectra 16,025 cm−1 and 23,474 cm−1 are assigned to 4A2g(F)→ 4T2g(F) and 4A2g(F)→ 4T1g(F) transitions, respectively. The site symmetry of Cr3+ is C4v or C3v. Racah parameters, crystal field (Dq) parameters and energy gap are evaluated from the optical spectra. Various other physical parameters like density etc. have also been reported.

Optical properties of zinc tellurite glasses doped with Cu2 + ions

Copper-containing ZnO–TeO2 glasses were synthesized using orthotelluric acid, zinc nitrate and the formed batch was doped with copper nitrate. EPR and optical spectra in a wide transparency range from were measured for all glass samples. The values of the spin-Hamiltonian parameters indicate that the Cu2+ ions in the glasses are present in octahedral coordination with some trigonal distortion. The molecular orbital bonding parameters have been calculated and were found to be independent of Cu2+ concentration in glasses. The optical transmittance spectra of doped glasses show a single broad band at 820nm, which was assigned to the overlapping 2B1g→2B2g, 2B1g→2Eg and 2B1g→2A1g electronic transitions. The spectral dependence of the specific absorption coefficient of Cu2+ ions was calculated for glass samples in the range of 310–2800nm and was found that the specific absorption coefficient at 820nm is (103±1) cm−1/(wt%) and the integral absorption coefficient in the range 0.5–2.8μm is (63±2) cm−2/(ppm wt). From the optical data some optical parameters such as the optical energy gap, Urbach energy, metallization criterion and the cut-off wavelength were calculated. It is observed that the optical band gap decreases with an increase in concentration of copper content.

Optical properties of the MoO3 – TeO2 glasses doped with Ni2 +–ions

The binary MoO3 – TeO2 glasses doped with 0–0.5mol% of Ni2+ ions were prepared by the melt-quenching technique using inorganic salts and acids as starting materials. The optical transmission spectra of all prepared glasses were studied in the wavelength range 0.5–6μm. Two broad bands with maxima at 744 and 1318nm are produced by octahedrally coordination nickel ions. The crystal field splitting energy and Racah parameters of Ni2+ ions were calculated by using the Tanabe-Sugano diagrams. The spectral dependence of the specific absorption coefficient of nickel was established and the value of the integral absorption coefficient in the wavelength range 0.6–2.8μm was found as (14.5±0.3) cm−2/(ppmwt). The value of the optical band gap is observed to decrease while the refractive index and Urbach's energy increase with increase in the concentration of Ni2+ in the glasses.

Short-range structure and thermal properties of alumino-tellurite glasses

Alumino-tellurite glasses with wide range of Al2O3 concentration (1 to 20-mol%) are prepared and their short-range structural and thermal properties are studied by Raman spectroscopy, 27Al Magic Angle Spinning Nuclear Magnetic Resonance (MAS-NMR) and Differential Scanning Calorimetry (DSC). Glass sample with 1-mol% of Al2O3 has TeO co-ordination of 3.66, which is close to the value of 3.68 reported in pure TeO2 glass. TeO co-ordination decreases steadily to 3.33 on increasing alumina content to 20-mol%. 27Al MAS-NMR studies found that Al ions exist in hexa, penta and tetrahedral co-ordination in the alumino-tellurite network. On increasing alumina content from 3 to 20-mol%, the concentration of hexa-co-ordinated AlO units decreases from 54% to 35% with a simultaneous increase in the concentration of penta and tetra co-ordinated AlO units. Glass transition temperature increases with increase in Al2O3 concentration and correlates directly with the average single bond enthalpy of the glass network.

Evaluation of physical, structural properties and shielding parameters for K2O–WO3–TeO2 glasses for gamma ray shielding applications

In the present work, a series of ternary glasses in the K2O–WO3–TeO2 system have been synthesized by conventional melt quenching technique. Glass formation range of the selected glass system was determined and physical, structural and radiation shielding properties of the glasses were investigated. Density (ρ), molar volume (VM), oxygen molar volume (VO), oxygen packing density (OPD), average cross-link density (nc¯), the number of bonds per unit volume (nb) and Poisson's ratio (μcal) values were evaluated for the interpretation of physical and structural properties. Fourier transform infrared (FTIR) spectra of the glasses were analyzed in order to obtain the information on the structural transformations in the glass network following the equimolar substitution of TeO2 by K2O + WO3 and changing K2O or WO3 at constant TeO2. Increasing K2O at constant TeO2 decreases the network connectivity due to the formation of non-bridging oxygen sites and the glass network became less tightly packed. On the other hand, equimolar substitution of TeO2 with WO3+K2O in these glasses resulted in a more compact glass network. The mass attenuation coefficients have been computed using WinXCom program and the obtained values were used to calculate the half value layer, the effective atomic number and the electron density. In addition, the macroscopic effective removal cross-section for fast neutron values are also evaluated. The variation of shielding parameters was discussed for WO3 variation in the glass composition and photon energy. From the derived results, it was found that K30W60T10 is the best glass in terms of shielding effectiveness among all the studied glasses due to higher values for mass attenuation coefficient, effective atomic number, and electron density and lower values of half value layer. These glasses show potentiality to be used as shielding materials and for an improved shielding effectiveness of the K2O–WO3–TeO2 glasses, a large WO3 content would be required.

Ho3+-doped AlF3–TeO2-based glass fibers for 2.1 µm laser applications

Ho3+-doped AlF3–TeO2-based glass fibers based on AlF3–BaF2–CaF2–YF3–SrF2–MgF2–TeO2 glasses are fabricated by using a rod-in-tube method. The glass rod including a core and a thick cladding layer is prepared by using a suction method, where the thick cladding layer is used to protect the core from the effect of surface crystallization during the fiber drawing. By inserting the glass rod into a glass tube, the glass fibers with relatively low loss (~2.3 dB m−1 @ 1560 nm) are prepared. By using a 38 cm long Ho3+-doped AlF3–TeO2-based glass fiber as the gain medium and a 1965 nm fiber laser as the pump source, 2065 nm lasing is obtained for a threshold pump power of ~220 mW. With further increasing the pump power to ~325 mW, the unsaturated output power of the 2065 nm laser is about 82 mW and the corresponding slope efficiency is up to 68.8%. The effects of the gain fiber length on the lasing threshold, the slope efficiency, and the operating wavelength are also investigated. Our experimental results show that Ho3+-doped AlF3–TeO2-based glass fibers are promising gain media for 2.1 µm laser applications.

Mechanical, Structural and Thermal Properties of Transparent Bi2O3–Al2O3–ZnO–TeO2 Glass System

Oxide based optical glass materials has important potential material in many applications from fiber optic to sensor due to the high transparency and amourphous structures. The objective of this study is to synthesize the novel optical glass materials based on the bismuth and aluminum contents to be able to determine the physical, chemical and mechanical properties by considering the systematic experimental steps. In this study, Bi2O3–Al2O3 based tellurite optical glasses have been prepared by using conventional melt quenching method as a function of the both Bi2O3 and Al2O3 compositions. There is a strong interactions between the glass former and modifier ions that might effect on the structure and mechanical properties. During the experimental steps, thermal, structural and mechanical properties of the prepared glass materials have been determined considering the DTA/DSC, FT-IR spectroscopy, SEM and Vicker’s hardness techniques, respectively. Thermal parameters, like glass transition, Tg, onset, Tx, crystallization, Tp, and melting, Tm, temperatures were obtained by using DTA scan.

Novel compositions of Bi2O3-ZnO-TeO2 glasses: Structure and hardness analysis

Tellurite based glasses have been prepared with various glass compositions such as yBi2O3-xZnO-(100−x−y)TeO2 glass system (y=0.2, 1.0, 2.0, 3.0, 4.0, 5.0, and 8.0mol% ratio and x=14, 19, 19.8, and 20mol%). The purpose of the work is to investigate the effect of glass compositions on the structure and hardness under the indentation loading test. Up till now, the experiences of the preparation of tellurite based glasses showed that it has high fragility structure at room temperature compared to boroxide, and chalcogenide-based glass materials. In this study, the thermal, mechanical and structural properties of Bi - based tellurite optical glass materials were investigated at room temperature. Results indicated that increased refractive index ratio of Bi has pronounce effect upon the transition temperature while the hardness value of the lassy material showed a reduction in response to this increased refractive index value of Bi. The obtained results further could be correlated with compositions that effects on the structural changes [for TeO4 (tbp) to TeO3 (tb)] having non-binding oxygen (NBO) due to the elastic deformation of TeO bonding and expansion of interatomic distances when considered the data of the Vickers' hardness, FT-IR, and Raman spectra. Here, it can also be emphasized that obtained the thermal stability, (T=Tx−Tg), of the glass material, decreases from 80 to 37°C as the melting temperature increases from 800 to 1025°C, possibly leading to a decrease in microhardness and deformation in the glass materials.

Study on Physical and Photoluminescence Properties of Er<sup>3+</sup>Doped Zinc Barium Tellurite Glasses

Er3+-doped ZnO – BaO – TeO2 glasses with the formula (80-x)TeO2–15ZnO–5BaO–xEr2O3 were fabricated using melt quenching technique. The 5 glass samples with different concentrations of Er2O3 were prepared under atmospheric pressure. The samples were investigated on their properties: density, molar volume, absorption spectra and photoluminescence. Density was increased with an increase in Er3+ content. The molar volume trend is in the opposite way to that of the density. The absorption bands are assigned as absorptions from the 4I15/2 ground state to the 4F7/2, 2H11/2, 4S3/2, 4F9/2, 4I9/2, 4I11/2 and 4I13/2 levels. All absorption bands are increase with increasing content of Er3+. The photoluminescence spectra were measured with 980 nm light pumped by flash lamp. The spectra trends to increase with increasing concentration of the dopant.

Synthesis, thermal and structural properties of pure TeO2 glass and zinc-tellurite glasses

We have synthesized pure TeO2 glass and glasses in the systems xZnO−(1−x)TeO2 (0≤x≤0.50) and yAl2O3−(1−y)TeO2 (0≤y≤0.03) by melting in Pt crucibles, and measured their glass transition temperature (Tg), density (ρ) and Raman spectra to correlate glass properties with structure. For pure TeO2 glass, synthesized using our newly developed intermittent quenching technique, we find onset- and midpoint-Tg at 301.1 and 306.7°C and ρ=5.62g/cm3, in clear disagreement with TeO2 glass melted in alumina crucible for which we find Tg≈380°C and ρ=4.86g/cm3. This latter method, used frequently in the literature, was shown by Raman spectroscopy to introduce Al2O3 in the tellurite matrix which becomes cross-linked by Te-O-Al bridges, resulting in the increase of Tg and decrease of ρ. Raman spectroscopy showed also that doping TeO2 with ZnO or Al2O3 causes the progressive conversion of TeO4 trigonal bipyramids to TeO3+1 polyhedra with two terminal oxygens, and then to TeO3 trigonal pyramids with three terminal oxygens. This structural transformation is reflected in the composition dependence of the volume per mole TeO2 evaluated from density data. The ZnO-dependence of this parameter is described by two linear parts with an inflection point at x=0.25, which indicates an increasing rate of forming terminal TeO bonds at higher ZnO contents. The Tg was found to increase with ZnO and Al2O3 contents and this was attributed to the glass-forming ability of both oxides, while density was found to decrease due mainly to replacement of the heavier TeO2 by the lighter ZnO and Al2O3. The results of this study are discussed with reference to previous works on TeO2 and zinc-tellurite glasses.