Polycarbonate samples were submitted to ageing at room temperature or at 8 degrees C after quenching from above T-g or de-ageing by pre-yield tensile deformation. toss curves were measured in the temperature range located between the beta and the alpha transitions. These curves exhibit an alpha' peak on the low temperature side of the alpha peak. The position of the alpha' peak is clearly dependent on the history of the sample: the alpha' peak located in the low temperature range after quenching or mechanical de-ageing is shifted to higher temperatures during further ageing. The time and temperature dependence of the alpha' peak location has shown that the kinetics of the alpha' relaxation near and below room temperature is controlled by a lower activation energy process than the annealing process prevailing near T-g and already identified. A classical formalism modified by taking into account two alpha' relaxation processes prevailing either at low or higher temperatures yields a good description of the alpha' loss curves of most samples aged for a long term at room temperature, but fa its to describe the alpha' peaks of specimens submitted to another ageing history. To model the loss curves of such specimens the relaxation time spectrum involved in the description of the alpha' peak is assumed to be dependent on the history of the sample and on the current test temperature.