Multiple Time Scales in Amorphous Materials

Amorphous materials display dynamic properties on many time scales from picoseconds to millions of years and – depending on the time scale of observation – may appear solid-like or liquid-like or something in between. Measuring this enormous span in time scales is a monumental challenge for experimentalists, and often several techniques are involved in the attempt. Here, a pedestrian introduction to the topic is given and a personal view of the current status of experimental achievements, focusing on the possible generic relaxation shape and a model for relaxation time that connects short-time elastic properties to the long-time viscous flow.