Effect of Overcooling and Stoichiometry Deviations on Kinetics and Mechanism of Crystallization of As2Se3 Glass

A comparative study of the kinetics of massive bulk crystallization of As2Se3, As1.9Se3, and As2.1Se3 bulk glasses at 240 degrees C is performed using the Kolmogorov-Avrami model. A theoretical analysis of the experimental dependences of the linear growth rate of As2Se3 crystals on temperature and viscosity of the As2Se3 glass is performed. It is shown that the dislocation growth of crystals in the form of spherulites appears to be probable in the As2Se3 glass under overcooling at increment T = 30-135 degrees C. For individual lamellar crystals As2Se3 with dislocation-free faces inside the spherulites, a growth mechanism with surface two-dimensional nucleation (2Dsg model) appears to be probable at increment T = 75-135 degrees C.