Thermally Stimulated Current (TSC) spectroscopy and Differential Scann
ing Calorimetry (DSC) have been applied to the characterization of the
microstructure of a pharmaceutical drug. The dielectric relaxation sp
ectrum shows two modes located in the temperature range of the glass t
ransition. They have been attributed to the molecular mobility in the
''true amorphous phase'' and in the <<rigid amorphous region>>.