A transform formulation of a heating rate 13 in differential scanning calorimetry (DSC) into frequency omega at the glass transition of polystyrene is proposed by using Duhamel's theorem, a superposition integral based on a linear response theory. A heat capacity spectroscopy in a frequency range of eight orders of magnitudes for glass transition of polystyrene, including the results of temperature wave analysis and all the literature values, is well fitted with a Vogel-Fulcher-Tamman-Hesse (VFTH) curve. The origin of the discrepancies is discussed. (C) 2011 Elsevier Ltd. All rights reserved.