Stabilization processes of metastable crystalline phases in 2,5-dichlorothiophene

Three crystalline phases, two metastable and one most-stable phase, were found in 2,5-dichlorothiophene by differential scanning calorimetry (DSC). The relaxation processes from one metastable crystalline phase to another and from this metastable phase to the stable phase were investigated by tracing the enthalpy change for a long time under constant temperature using DSC. The Avrami index n, in the Avrami equation, was found to be approximately 2 for both relaxation processes.