On the frequency correction in temperature-modulated differential scanning calorimetry of the glass transition

Temperature-modulated differential scanning calorimetry (TMDSC) is based on conventional DSC but with a sinusoidally modulated temperature path. Simulations of TMDSC signals were performed for Corning EAGLE XG glass over a wide range of modulation frequencies. Our results reveal that the frequency correction commonly used in the interpretation of TMDSC signals leads to a master nonreversing heat flow curve independent of modulation frequency, provided that sufficiently high frequencies are employed in the TMDSC measurement. A master reversing heat flow curve can also be generated through the frequency correction. The resulting glass transition temperature from the frequency corrected reversing heat flow is thereby shown to be independent of frequency.

► Frequency correction can lead to a master non-reversing heat flow curve independent of modulation frequency. ► Frequency corrected reversing heat flow can give identical glass transition temperature as from cooling cycle. ► Narrow Tg range for quenched and rejuvenated glass reveals similar constraints controlling the glass transition. ► Frequency corrected non-reversing heat flow gives same aging enthalpy as that from total heat flow.