Temperature modulated DSC - Theoretical interpretation

The application of non-linear heating program to a heat-flux DSC apparatus has attracted much attention. From thermodynamics viewpoint, it is shown th at the variation of enthalpy of a sample changing with temperature change i s due, to both the true heat capacity of the sample and the enthalpy of som e transformations occurring in the sample, characterized by its degree of a dvance. Using the simple assumption that the rate of the transformation is proportional to the distance from the thermodynamic equilibrium, an electri cal model of the thermal event is given. Using the coupled cell model of th e DSC apparatus, we show how to obtain the rate of transformation of the sa mple and heat capacity, which is directly related to the base line of the e xperiment.