Non-isothermal study of the devitrification kinetics of fluoroindate glasses

The understanding of the kinetics of devitrification of a glass is important for anticipating its stability in a particular purpose, such as fiber-drawing processes. The crystallization kinetics of (BaF2)(16)(ZnF2)(20)(SrF2)(20)(NaF)(2) (GaF3)(5)(InF3)(36)(GdF3)(1) glass prepared by quenching were studied by differential scanning calorimetry (DSC), Avrami's exponent (n) obtained by a non-isothermal method was 4.3 for a solid and 2.4 for a powdered sample. According to the classical interpretation of n, these magnitudes correspond to an interface-controlled crystal growth and a diffusion-controlled crystal growth, respectively, The activation energies for crystallization (E) was 62 +/- 1 kJ/mol for solid glass and 245 +/- 2 kJ/mol for powdered glass. These results are discussed in terms of glass particle size. (C) 2000 Elsevier Science B.V. All rights reserved.