In the present study, a complete model of thermal diffusion in a TMDSC specimen was developed. The numeric simulation of the temperature evolution takes into account the transient terms at early times and assesses the time at which these vanish. The simulation also provides a complete temperature profile in both radial and axial direction within a cylindrical specimen, and underlines the existence of non-negligible temperature gradients within a polymeric sample. The model predicts a heat flow phase based on the thermophysical properties of the specimen, and avoids the use of a complex heat capacity which has no well-founded physical or thermodynamic meaning. Good agreement was found between experimental and predicted heat flow phase angles.