Abstract: The effect of 4wt%TiO₂ and 2wt%TiO₂+2wt%ZrO₂ on the nucleation and crystallization of Li₂O-
Al₂O₃-SiO₂ system glass was investigated by the method of differential thermal analysis (DTA), the differential thermal analysis (DTA), X-ray
diffraction (XRD) and the scanning electron microscopy (SEM). As the glass nucleates with a different thermal schedule, the crystallization peak
temperatures all shift to lower temperatures. The changes of nucleation temperature and nucleation peak height of the glass added with single TiO₂
are larger than that of the glass added with TiO₂+ZrO₂. That means when TiO₂ is used as nucleation agent, crystallization is more sensitive as
the variation of nucleation temperature than that of the glass added with TiO₂+ZrO₂. As all nucleation time is 2h, when TiO₂ is used as nucleation agent,
the most effective nucleation temperature is 745℃, when TiO₂+ZrO₂ is used as nucleation agent, the most effective nucleation
temperature is 760℃. When heat treated at most effective thermal schedule, the samples have grain sizes of 100～150nm for TiO₂ as nucleation agent,
and of 50～80nm for TiO₂ +ZrO₂ as nucleation agent.

Key words: differential thermal analysis, glass-ceramics, nucleation, crystallization