An equation for the retardation time for enthalpy recovery has been tested for polystyrene as a function of heating rate, temperature, and initial displacement. The temperature dependence &Vthgr; and displacement dependence &xgr; of the retardation time are determined from the data assuming a single relaxation time. The fraction of the temperature dependence of the retardation time due to structure (1−X) and due purely to temperature (X) are calculated and compared with results for other polymers. Some factors which can affectXare discussed.