Glass transition temperature (Tg) studies on poly-α-methylstyrene havingMnvalues ranging from 2.9 × 103to 7.0 × 104were carried out with the DSC-2 differential scangng calorimeter. The variation of Tge(at q = l°K/min) withMnobeys the relation, Tge(°K) = 453–3.1 × 105Mn. The enthalpy change ΔH observed near the glass transition temperature drops to zero for zero annealing time and zero extrapolated heating rate conditions, suggesting that it is not necessary to postulate a first order transition to account for energy absorption. Operating with longer annealing periods or low heating rates yields similar trends as far as the AH values are concerned. Tgextrapolated to zero ΔH for zero extrapolated heat-ing rate conditions was found to increase with increasing annealing time.