The glass transition temperature T-g of polymers - Comparison of the values from differential thermal analysis (DTA, DSC) and dynamic mechanical measurements (torsion pendulum)

It is often maintained that the glass transition temperatures determined by dynamic mechanical thermal analysis (DMTA) are higher than the corresponding glass transition temperatures measured by differential thermal analysis (DTA, DSC). Examination of a large number of polymeric systems revealed that this statement is not generally true when a torsion pendulum with a frequency of measurement of 1 Hz is used as the DMTA instrument. On the contrary, it is found on average that the relationship T(g,TP)approximate toT(g,DTA) holds. (C) 2000 Elsevier Science Ltd. All rights reserved.