Crystallization kinetics in a lithium disilicate glass revisited: Model-free and model-fitting approaches

The present work estimated the crystallization activation energy, Eα, the pre-exponential term, A, and the reaction model, g(α), of a lithium disilicate glass using model-free and model-fitting approaches. Samples with distinct granulometry (PD1: < 105 μm; and PD5: 600–850 μm) were heated at several rates (0.5 to 30 K/min). Our results show that Eα, A, and g(α) are susceptible to particle size. PD1 crystallizes in a single step, and the surface mainly governs it all β values. On the other hand, the overall crystallization of PD5 is more complex and can be described by different Avrami reaction models, with n = 1, 1.5, 2, and 3. In addition, we found that the crystallized fraction at the crystallization peak (αTp) varies significantly with the particle size and heating rate, which confirms that all the methods that assume that the αTp is constant are inadequate to describe the crystallization of glasses over a wide range of heating rates.