Optical study of lead borosilicate glasses

Glasses with compositions xPbO–RNa2B4O7–(100−R−x)CAS (0.49CaO, 0.21Al2O3, 0.3SiO2) with 0≤x≤50 and 50≤R≤75 mol% have been prepared using the normal melt quenching technique. The optical transmittance and reflectance spectrum of the glasses have been recorded in the wavelength range 300–1100 nm. The values of the optical band gap Egopt for indirect transition and refractive index have been determined for different compositions of the amorphous glass. The average electronic polarizability of the oxide ion αo2− and the optical basicity have been estimated from the values of calculated refractive indices. The compositional dependence of the different physical parameters such as the density, the optical band gap, the refractive index, the average electronic polarizability of the oxide ion and the optical basicity on PbO content have been analyzed and discussed.