Effect of Li2O on the heterogeneous structure of equi-molar lead borate glasses

Different glass samples in the Li2O, PbO and B2O3 system have been prepared by melt quenching method. These glasses were classified in two groups such as 0.5 B2O3, (0.5 − x) PbO, xLi2O and (0.5 + y) B2O3; (0.25 − y)PbO; 0.25Li2O. The IR spectra almost show broad bands in the frequency range (800–1050) cm−1 and (1100–1500) cm−1, together with different weak bands over the range of investigation (2400–3000) cm−1. The deconvolution analyses of these IR spectra reveals presence of multi structure arrangements from BO4 and BO3 groups, such as penta, tri, and diborates grouping together with meta; ortho borates as well as PbOn groups. Partial replacement of PbO by Li2O causes decrease in microhardness, a change which is attributed to the decrease in the concentration of ortho borate groups as is it revealed from the bands area analysis. The IR analysis shows also that the total concentration of (meta + ortho) borates is nearly constant while their individual concentrations is proportional depending on the relative concentration of PbO and Li2O.