Dielectric Relaxation and Crystallization of Ultraviscous Melt and Glassy States of Aspirin, Ibuprofen, Progesterone, and Quinidine

Evidence for a New Crystalline Phase of Racemic Ibuprofen

“…1b). We found Tg= 228±1 K (inflexion point temperature), in agreement with the value obtained by Brás and co-workers (12) and Johari and co-workers (13). The heat capacity jump at the glass transition is 76±1 J/mol.K.…”

Dielectric Spectroscopy in Ibuprofen-Dioxane Mixture

“…When g k >1, indicates the tendency of parallel alignment of neighboring dipoles and g k < 1, indicates the tendency of anti-parallel alignment of neighboring dipoles. Here, the small values of ∆ε are in agreement that hydrogen bonding in these samples favors an anti-parallel correlation of the neighboring dipoles [1,7,32]. Some information of the dipole moment (µ 0 ) is necessary to understand the dielectric strength variation.…”

Role of Thermodynamic, Molecular, and Kinetic Factors in Crystallization from the Amorphous State

“…(b) Molecular mobility in the glass may also move the entire system homogenously structurally toward the more stable crystalline form and perhaps nucleating, (c) since there exists a distribution of substates and relaxation times, substates characterized by higher mobility may result in localized nucleation in the glassy state. 64 The authors suggested that a combination of these three factors may contribute to the overall physical stability of amorphous system below its glass transition temperature. The present section will therefore focus on the correlations between different measures of molecular mobility and crystallization both in a single component system and a multicomponent system.…”