Fig. 4: Thermal and structural characteristics of initial and aged glasses.

Since its preparation, the as-cast Ce₆₅Ga₈Cu₂₂Nb₅ MG has aged at room temperature for ~10.5 years, while the age of Baltic amber is between 35 and 50 million years^49,50. Both the long-term aged a Ce₆₅Ga₈Cu₂₂Nb₅ MG and c amber exhibit a significant endothermic overshoot compared to their corresponding rejuvenated samples. b, d The XRD spectra of both long-term aged and rejuvenated samples show an amorphous state, and the insets show photographs of the two hyperaged samples.