Real-time microscopy of the relaxation of a glass

The understanding of the dynamics of a glass above its devitrification temperature remains incomplete. Here, we build a spatio-temporal map of the relaxation dynamics of a highly stable glass into its supercooled liquid using real-time atomic force microscopy imaging. This methodology enables direct visualization of the progression of the liquid phase and clarifies and quantifies the presence of localized fast mobility regions separated by giant length scales. Our data establish a clear correlation between dynamic length and time scales in glasses. This approach may also be applicable to unveil the microscopic structure and dynamics of other glass-forming systems with much shorter length and time scales, including liquid-cooled glasses. Visualizing dynamical changes in glassy systems is challenging because of the time and length scales involved. Now, atomic force microscopy is shown to be a viable method for obtaining a spatio-temporal description of the relaxation of a glass.