Viscoelastic Properties And Molecular Mo Near The Glass Transition Range

The viscoelastic properties of glasses with different cohesive forces were measured near their Tg by means of low frequency mechanical spectrometry. The glasses which were studied presented different ratios of mean strong/weak constraint per atom. By increasing this ratio, we have molecular and ionic glasses and then network glasses. The dynamic behaviour thus observed was analysed at a microscopic level through a modellisation based on physical concepts of defects and hierarchial constraint dynamics of disordered matter.