Effect of ZnO on the Physical and Optical Properties of Tellurite Base Glasses

Glass samples in the system 60 TeO2 - 10 B2O3- (30-x) Bi2O3-x ZnO with mole fraction x = 10, 15, 20, 25 and 30 were synthesized by conventional melt quenching technique under controlled atmospheric conditions. The glassy nature of the synthesized glass samples have been confirmed by X-ray diffractogram. It is observed that density (d) and molar volume (V-m) decreases with ZnO concentration and the same trend is also followed by theoretical calculations of crystalline density (d(c)) and crystalline volume (V-c). The theoretical optical basicity and electronic polarizability both decreases with increase ZnO content. The fundamental absorption edge or cut off wavelength shifts to the lower wavelength side and increase of E-op to higher energies with increase in zinc content is related to the increase in the concentration of the bridging oxygen (BO) atoms.