Kinetics of non-isothermal cold-crystallization of carbamazepine in the glassy state studied by DSC

Kinetics of non-isothermal cold-crystallization of quench-cooled carbamazepine (CBZ) was investigated under different heating rates using Differential Scanning Calorimetry. Relevance of Johnson-Mehl-Avrami, Kissinger, Augis-Bennett, Ozawa, Mo and Matusita models to describe the mechanism of nucleation and growth was thoroughly discussed. Some assumptions of Johnson-Mehl-Avrami and Kissinger models were showed to be inadequate when describing kinetics of cold-crystallization of quench-cooled CBZ. Augis-Bennett, Ozawa and Mo models correctly outlined the nucleation and growth mechanism, however they were not able to distinguish between surface and bulk crystallization. Matusita model was the only one which properly described these two mechanisms and consequently was considered as the most versatile one. Quench-cooled CBZ displayed two different crystallization mechanisms for lower and higher heating rates. In the first case, surface crystallization was dominant, whereas in the second case - the bulk one. Activation energy was noticed to be heating rate, temperature and fractional extent of crystallization dependant.

Automated summary

In this study, the kinetics of non-isothermal cold-crystallization of quench-cooled carbamazepine (CBZ) were investigated using Differential Scanning Calorimetry under different heating rates. Various models were discussed for describing the mechanism of nucleation and growth, with the Matusita model being considered the most versatile one. It was found that the Matusita model properly described both surface and bulk crystallization mechanisms in different conditions of heating rates.