Structural relaxation in annealed hyperquenched basaltic glasses: Insights from calorimetry

► A nearly identical glass transition temperature (Tg) was observed for both the hyperquenched (HQ) and annealed HQ glasses. ► The origin of the abovementioned phenomenon has been explained. ► The enthalpy recovery during sub-Tg annealing is mainly associated with secondary relaxation. ► A distribution of fictive temperatures is responsible for the broad distribution of relaxation times of HQ glasses.