Influence of the preparation method (thermal quench, ball-milling, dehydration and freeze-drying) on the dynamical properties of glassy trehalose

Dielectric relaxation measurements have been performed on the glassy states of trehalose reached using different routes of amorphisation: thermal quench of the liquid state, milling of the anhydrous crystalline form, freeze-drying and dehydration of the dihydrate crystalline form. This study has revealed that all the glassy states are characterized by two relaxation processes respectively attributed to the slow Johari-Goldstein mode and to fast secondary intramolecular relaxations. These sub-Tg secondary relaxations are however strikingly different in the four glassy states revealing different energy landscape topologies.