Effect of the addition of TiO2, ZrO2, V2O5 and Nb2O5 on the stability parameters of the Li2O-BaO-SiO2 glass

Glass stability (GS) parameters based on typical temperatures obtained by differential thermal analysis were determined for glasses composed of Li2O:BaO:SiO2:nucleant, using TiO2, V2O5, ZrO2 and Nb2O5 as nucleants. The GS parameter proposed by Saad and Poulain, S, showed values of 21.26 for ZrO2, 13.77 for Nb2O5, 11.42 in the glass without nucleating agent, 6.91 for V2O5 and 6.29 in that containing TiO2. GS was also inferred from the apparent activation energy of crystallization, AE, and these values of the compositions, in kJ mol− 1, were 355 in the glass without nucleating agent, 322 for TiO2, 254 for ZrO2, 278 for V2O5 and 300 for Nb2O5. A surface crystallization mechanism was observed, and thermal treatment yielded crystalline Li2Si2O5 and Li2SiO3. The time-temperature-transformation diagrams, TTT diagrams, were consistent with the obtained GS parameters.