The role of lead oxide on structural and physical properties of lithium diborate glasses

Pseudo-binary (100 − x)Li2B4O7–xPb3O4, with x = 0–70 mol% PbO have been prepared and their properties investigated. The glass transition temperature, density and molar volume have been determined as a function of composition. The values of Tg and the molar volume decrease non-linearly while the density increases as the Pb3O4 content is raised. Infrared spectra of the glasses reveal that a strong network consisting of diborate units breaks up by the addition of Pb3O4. The absorption bands below 620 cm−1 show that PbO is one of the network formers of the glasses 70 ⩾ Pb3O4 ⩾ 10; as they can be associated with vibrations of (PbO4)2− grouping. PbO plays a dual role in the glass network. The calculated values of N4 [the fraction of borons which are tetrahedral] slightly decrease with PbO content up to 30 mol% and then increase with Pb3O4 content up to 50 mol%, then followed by a decrease as the Pb3O4 content rises further. The Vickers hardness of the glasses varies as a function of the PbO content in the same manner as the variation of N4. The dc conductivity decreases with the Pb3O4 concentration up to about 30 mol% and then increases thereafter.

► We prepare Li2B4O7–Pb3O4 glass samples by the quenched method as bulk.
► The effects of substitution Li2B4O7 with Pb3O4 in glass composition are studied.
► The structure, density, Vickers hardness, glass transition temperature and electrical properties have been influenced by these substitution.