Relaxation of surface tracks on polycarbonate thin films induced by MeV heavy-ion impacts

In the present work, the relaxation behavior of nanometer-sized deformations produced by single ion impacts on the surface of monodisperse (Mw=60,000u) polycarbonate thin films was investigated at temperatures close to and below the glass transition. The relaxation functions for the length, height and width of the deformations were well described by a stretched exponential law, with characteristic relaxation times τ strongly dependent on temperature. For T>100°C, the temperature dependence of τ obeys a Vogel–Fulcher law, but for lower temperatures it becomes less steep and tends to an Arrhenius-type behavior.