Chemical bonding and glassy activated dynamics in equilibrated network liquids

One of the most striking phenomena in amorphous materials is the rapid onset of rigidity at decreasing temperatures, known as the glass transition. One successful approach to understanding the glass transition is the Random First-Order Transition (RFOT) theory of glasses, which explains that the viscosity of supercooled liquids is governed by an energy scale corresponding to the activation barrier to locally rearrange a droplet of particles. Both the length and energy scales of glassy activated events grow with decreasing temperatures in manners predicted by RFOT theory and confirmed by experiment. A specific class of glasses, the so-called "network glasses", features long-lived interactions, such as covalent bonding, which act as a constraint on the spatial motion of bonded particles. Network glasses can be found anywhere from everyday window glass (silica mixed with alkali oxides) to more exotic colloidal and biological systems. In many network glasses, the bonding dynamics and glassy activated events have comparable energy and time scales. How do the properties of glassy activated events change when bonding dynamics compete with the overall rearrangement dynamics? Some previous work predicted the thermodynamic properties of network glasses from RFOT theory, which I here expand to describe dynamical properties.