Optical Properties of quaternary TeO2-ZnO-Nb2O5-Gd2O3 glasses

Quaternary tellurite glass systems in the form 75TeO2-15ZnO-(10−x)Nb2O5−xGd2O3, where (x=0.0, 0.5,1.0,1.5,2.0 and 2.5 mol%) have been prepared by the melt quenching technique. Optical absorption studies are carried out on the glass systemin the wavelength range of 380-500 nm. The cut-off wavelength λc, optical band gap Eopt, Urbach energy ΔE and refractive index n values were calculated from optical absorption data. Also, different physical parameters such as, molar refraction RM, metallization criterion M, electronic polarizability of the oxide ion αo2− (calculated from Eopt), and optical basicity Λ have been determined. The FTIR absorption spectra for all glasses in the range of wave numbers 350-4000 cm−1 has been recorded and designated.