Faucher investigated the stress relaxation behaviour of isotactic polypropylene at temperatures between -67 and 140 degrees C and found that a master curve could be formed by applying the principles for thermorheologically simple (TRS) materials. Since a previous investigation by the authors has shown that the TRS principle fails to model the viscoelastic performance of isotactic polypropylene consistently, Faucher’s data are reanalysed on the basis of a two-component model. Application of the model leads to a good fit of the experimental data. The component moduli as well as the characteristic relaxation time show pronounced temperature dependencies and three different transition temperatures between -27 and +28 degrees C. In Arrhenius plots the parameter values follow sigmoidal curves that differ in intensity and position but show a similarity in their shape, indicating comparable distributions of activation energies underlying the transitions. The consistency of the results is checked against tan delta data from dynamic, extensional tests. The diversity of the responses of the model parameters to temperature is considered as a reason for the variability of the glass transition temperatures measured for isotactic polypropylene using different techniques.