We have carried out temperature-modulated differential scanning calorimetry (TMDSC) measurements on a typical chalcogenide glass system, As²Se³, which has been well-characterized previously in the literature by conventional DSC. We have studied the behavior of the total and reversing heat flows as the glass is cooled from a temperature above the glass transition temperature, that is, from a liquid-like state. The glass transition temperature Tg was operationally defined as the temperature where the reversing heat flow evinces an inflection point in changing from liquid-like to solid-like behavior. We have studied (a) the dependence of Tg on the cooling rate q under conventional DSC conditions and (b) the dependence of Tg on the modulation period P under TMDSC conditions. These two studies were carried out towards characterizing the glass relaxation kinetics. We have also examined whether Tg shows any dependence on the modulation amplitude A at a given cooling rate.