Boson peak and fast relaxation process near the glass transition in polystyrene

Abstract

Atactic polystyrene, both side group and main chain deuterated, was investigated by inelastic neutron scattering in a wide temperature range around the glass transition from 2 to 450 K. In the glass the Boson peak position is only very weakly influenced by the deuteration of the phenyl group. In the neighborhood of the glass transition temperatureTg we find a fast relaxation process similar to other glasses. The onset of the fast relaxation in polystyrene, however, is observed already at temperaturesTg — 200 K. Results from partially deuterated polystyrene suggest a change of the phenyl ring dynamics already far belowTg.