科研之友
微信
新浪微博
Facebook
分享链接
摘要
beta relaxation, which is predicted by mode coupling theory and involves the localized motions of particles, initiates in a supercooled liquid and continues into glassy state. It correlates essentially with many fundamental properties of amorphous materials. Despite its importance, the underlying mechanisms leading to the beta relaxation have remained elusive. As natural heterogeneity, the original distributed free volume has been supposed to be associated with the activation of beta relaxation in amorphous solids. However, there has been no direct experimental proof for this hypothesis. Here we used a colloidal glass to directly observe the beta relaxation and free-volume distribution. We found a spatial correlation between the beta relaxation and free volume. The large free volume regions were observed to possess a low-energy cost of relaxation-induced strain, indicating that the large free volume region presenting a low-energy barrier for structural relaxation benefits the beta relaxation.
