Some structural and optical properties of (Bi2O3)x(ZnO)60−x(B2O3)40 glasses

Series of (Bi2O3)x(ZnO)60−x(B2O3)40 glasses were prepared from pure oxides. The dilatometric glass transition temperature decreased from 484 to 382 °C and the coefficient of thermal expansion increased from 5.3 to 9.5 ppm °C−1 for 10 ≤ x ≤ 50. From Raman scattering spectra and far infrared spectra it is suggested that the major Bi based structural entities are BiO6 units. The optical band gap was determined in the region 3.4–3.82 eV and the coefficient of the temperature dependence of the optical gap for the temperatures between 30 and 250 °C was found nearly constant at around (4.5 ± 0.5) × 10−4 eV K−1. The non-linear refractive index of the studied glasses was estimated from the optical band gap values in the region 6–9 × 10−12 esu.