Fast-sol-gel derived silsequioxane glasses embodying glycerol moieties: Dielectric properties and morphology

The fast-sol-gel synthetic route was utilized to prepare glassy matrices of varying porosity. Glycerol doping of these matrices was carried out at various stages of the sol-gel reaction. Dielectric spectroscopy data were collected from all these matrices, and interpreted in terms of various relaxation processes from which the internal morphology of the matrices could be deduced. Glycerol dopant added to the sol-gel-derived glass during preparation is adsorbed and partly chemically bound at the ends of the polymer-like chains of the matrix, acting as a cross-linking agent. It does not form bulk moieties at concentrations up to 2%. Cluster glycerol moieties are formed inside the glass at a concentration of 4%.