title: Direct visualization of free-volume-triggered activation of β relaxation in colloidal glass.
abstract: β 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 β relaxation have remained elusive. As natural heterogeneity, the original distributed free volume has been supposed to be associated with the activation of β 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 β relaxation and free-volume distribution. We found a spatial correlation between the β 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 β relaxation.
authors: School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028, People's Republic of China.
authors: Yunzhuo
authors: Y
authors: Lu
authors: School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028, People's Republic of China.
authors: Xing
authors: X
authors: Lu
authors: School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028, People's Republic of China.
authors: Zuoxiang
authors: Z
authors: Qin
authors: School of Materials Science and Engineering, Tongji University, Shanghai 201804, People's Republic of China.
authors: Jun
authors: J
authors: Shen