The investigation of the influence of lead oxide on the formation and on the structure of lithium diborate glasses

Pseudo-binary (100 − x) Li2B4O7·xPbO, where x = 0, 5, 15, 25, 35, 45, 55 and 65 mol%. PbO have been investigated. The glass transition temperatures, density and molar volume have been determined. Both Tgʹs values and molar volume decreased non-linearly while the density increased by increase the PbO content. Infrared spectra of the glasses reveal that the strong network consisting of diborate units is break open by PbO. The absorption bands below 620 cm−1 show that PbO is one of the network former of glasses 65 ≥ PbO ≥ 5 which can be associated with vibrations due to [PbO4]2− type of grouping are become sharp and high intensities by increase PbO content. PbO plays the dual role in the glass network. The calculated values of N4 slightly decreased by increase PbO content up to 25 mol% and then increased up to 45 mol% PbO, then decreases above it. Proving that three-coordinated boron atoms are predominant in these glass samples. The Vickerʹs hardness values of the glasses vary as a function of the PbO content in a manner that N4 varied. The dc conductivity decreased by increase PbO concentration up to about 25 mol% and then increased by increase the concentration of lead oxide.