Study of structure and optical properties of Fe2O3·CaO·Bi2O3 glasses

Glasses with compositions 0.05Fe2O3·0.95{xCaO·(100 − x)Bi2O3} (20 ≤ x ≤ 40 mol.%) have been prepared using the normal melt quench technique. The density and molar volume have been determined. Infrared (IR) spectroscopy is used to investigate the structure of the glass matrix. The optical studies in the UV–VIS–NIR region for all these glasses show a sharp cutoff and a large transmitting window. The values of both of the optical band gap (Eg) and width tails (ΔE) are determined. It is observed that Eg is decreased and ΔE increased with the increase of CaO in the glass matrix. The metallization criterion (M), interaction parameter (Ath), average electronic polarizability of the oxide ion (αO2−)(αO2−) and optical basicity (Λ) of these glasses are determined from the values of optical band gap. Small value of M   makes them appealing candidates for non-linear optical materials. Both αO2−αO2− and Λ increase with increase in CaO content. The compositional dependence of the above properties are discussed and correlated to the structure of the glass.