Optical and structural properties of ZnO-PbO-B2O3 and ZnO-PbO-B2O3-SiO2 glasses

Borate and borosilicate glasses with compositions of xZnO-2xPbO-(1-3x) B2O3 and xZnO-2xPbO-1/2(1-3x)B2O3-1/2(1-3x)SiO2 with x varying from 0.1 to 0.26 mole fraction were prepared by the conventional melt quench technique. Optical and structural properties have been determined by using ultraviolet-visible (UV/vis) and Fourier transform infrared (FTIR) spectroscopic techniques. Decreases in the band gap from 3.57 to 2.62 eV for borate glasses and from 3.00 to 2.35 eV for borosilicate glasses with an increase in the metal oxide content is observed. The density and molar volume has also been measured. Increases in density from 3.994 to 6.339 g cm(-3) for borate and from 4.221 to 6.548 g cm(-3) for borosilicate glasses are observed with an increase in metal oxide (PbO, ZnO or PbO + ZnO) content. Changes in the atomic structure with composition are observed due to the formation of BO4- units.