Thermal analysis of repetitive single crystallization events in glass-forming liquids at low undercooling

Thermal analyses of 284 repetitive single crystallization events were carried out. In particular, the isothermal liquid-to-crystal transformation kinetics of Poisson-distributed and non-Gaussian shaped exothermic DSC signals are calculated individually and by superimposition. It is found that modes of impingement for anisotropic growth, random and regular dispersions fail to accurately predict the growth exponent if a single crystal or a low number of crystals are growing. Non-stationary effects are evident at low and large crystal fractions which diminish when virtual signals of multiple crystallization events are superimposed. The results show that the precise analytic formulation to calculate the degree of transformation relies on an ensemble of crystals growing simultaneously. Where this is not the case, as in glass-forming liquids cooled from above liquidus temperature, the proper approach is to use a time-averaged signal of repetitive crystallization runs.