Study of physical ageing in amorphous polymer by thermo-stimulated currents (TSC)

The physical ageing in amorphous polymer, polycarbonate, is studied by complementary techniques: thermally stimulated currents (TSC) and differential scanning calorimetry (DSC). The enthalpy relaxation is described by using the Tool, Narayanaswamy and Moynihan (TNM) phenomenological model where the relaxation time /spl tau//sub H/(T,T/sub f/) depends both on temperature T /sub f/and fictive temperature Tf characteristic of the glass structure. We have shown the structural dependence of enthalpy relaxation time give prominence to the compensation law observed in dielectric relaxation times.