For the post-impact glasses, structural analyses were performed by HRTEM and SAED. The thermal response of glasses was investigated with differential scanning calorimetry (DSC; TA Q2000): heating the glass up to 823 K in a pure argon atmosphere at a heating rate of 20 K/min and subsequent cooling to room temperature at the same rate. The specific heat capacity was measured under high vacuum conditions with a Quantum Design physical property measurement system (PPMS), which allows cooling down to 2 K with a liquid helium system. For comparison, both DSC and PPMS measurements were also performed on the original as-cast glasses.