Abstract
Dielectric relaxation studies were carried out on unfilled and silica particle filled highly crosslinked PDMS samples, at temperatures above the calorimetric glass transition temperature. Our experiments suggest that the main a relaxation peak is preceded by a pre - a relaxation one, whose characteristics are not dependent in their nature on the presence of the reinforcing silica particles. This suggests that its presence may be characteristic of the high crosslink density PDMS. Keywords: highly crosslinked siloxane elastomers, silica filler, dielectric relaxation in the glass transition region, a-relaxation