Structural Evolution during Evaporation of a 3-Glycidoxypropyltrimethoxysilane Film Studied in Situ by Time Resolved Infrared Spectroscopy

"Time resolved infrared spectroscopy has been applied to study in situ the. evaporation process of a 3-glycidoxypropyltrimethoxysilane hybrid sol by casting a droplet on. a ZnSe substrate; the analysis has been performed in the middle-infrared range and in the. near-infrared range. The experiment has allowed following the structural changes induced by. water evaporation and the formation of ordered structures within the cast film; the CH2. scissoring bands have been used as a fingerprint for the disorder to order transition of the. hybrid. The experiment has been done using both a fresh sol and an aged sol which produce. respectively an amorphous material and a crystalline hybrid material. The analysis has shown. that the epoxy groups do not react during the evaporation while the silica structure shows only. a slight condensation and an increase in open cage-like species. At the end of evaporation the. hybrid has a “soft-like” state which allows structural rearrangements to self-order."