APS/Alan Stonebraker; Relaxation curves adapted from R. C. Welch et al. [1]

Figure 1: As the temperature is decreased, the viscosity of a supercooled liquid becomes exponentially large and so does the relaxation time towards equilibrium (black curve). Welch et al. [1] have shown that in a commercial glass plate, the relaxation time behavior in the nonequilibrium glassy state changes at the glass transition temperature $Tg$ and is about $19,000$ years at room temperature (red curve). The relaxation is not a product of viscous flow but rather originates in the nature and the number of relaxation channels. These effects are imposed by the underlying network structure, which is made of an aluminosilicate tetrahedral network disrupted by alkali cations.