Electronic Polarizability and Optical Basicity of BaO-B2O3-TeO2 Glass System

[(TeO2)0.7(B2O3)0.3]1-x (BaO)x, x = 0.00, 0.05, 0.10, 0.20, 0.25, 0.30 and 0.35 mol fraction glass series were successfully synthesized by conventional melt quenching method. Amorphous phase of all samples was confirmed through X-ray diffraction while optical properties were determined using UV-VIS spectrophotometer. Fourier Transform Infrared (FTIR) analysis showed that the glass structure consisted of TeO3, TeO4, TeO6, BO3 and BO4 structural units. The optical band gap energy, Eopt which was calculated from Tauc’ plots decreased as the amount of BaO increases, whereas, the Urbach energy value increased. The increase in Urbach energy value was attributed to the increase of defects in glass structure. The refractive indices of glass were found to increase along with the increased amount of BaO, due to the high polarization and high density of host material and glass modifier. The molar polarizability, αm, oxide ion polarizability, αo2- and optical basicity, Λ of the glasses are calculated by Lorentz-Lorenz equation. The glasses were found to possess αm values between 8.106 – 8.489 Å3, and αo2- values between 3.303 to 4.772. Meanwhile, optical basicity increases from 0.115 to 0.893.

Optical, Thermal and Radiation Shielding Properties of B2O3 - NaF - PbO – BaO - La2O3 Glasses

The techniques of melt-quenching were used to generate 53B2O3 - 2NaF - 27PbO – (20 - x)BaO - La2O3 (0 ≤ x ≥ 15) glass system. XRD patterns have established the amorphous character of glass samples. There is clear evidence of the role of La2O3 modifier in the glass network. The thermal characteristics were identified to increase with an increase in La2O3 content. Increasing La2O3 increases the linear and non-linear optical bandgap energy and the Urbach energy. By adding La2O3 to the glass samples, the refractive index, molar polarizability, polarizability, and optical basicity are increased. Theoretically, the bulk modulus and the glass transition temperature increase because of the increase in bond strength. The number of bonds per unit increased with the increase in La2O3 content because of the modifier character of La2O3 in the glass samples. Multiple optical parameters (ε∞), (εo), X(1), (X(3)) and (n2) as a function of linear and non-linear Eopt were obtained. The extent of shielding in this article was examined with the increment in La2O3 at the expense of BaO. The results correspond with similar studies conducted previously.