Thermal behavior of trehalose dihydrate (Th) and ?-anhydrous trehalose (T?) by in-situ laboratory parallel-beam X-ray powder diffraction

Thermal behaviors of trehalose dihydrate (Th) and ?-anhydrous trehalose (T?) have been investigated by in-situ laboratory parallel-beam X-ray powder diffraction. Data indicate that both phases show essentially the same volume expansion but expansion of the anhydrous form is markedly anisotropic due to the features of the hydrogen-bond network. Under the present experimental conditions, dehydration starts at 66 °C and within the 75 < T <114 °C the presence of the T? anhydrous polymorphic form has been detected.