Volume Relaxation Far from Equilibrium

Narayanaswamy's model of structural relaxation is applied to the data of Hara and Suetoshi on volume relaxation in plate glass. Both the Adam‐Gibbs and Arrhenius equations are used to represent the relaxation time. Equally good fits are obtained with both equations, but only the Adam‐Gibbs model gives Physically meaningful fitting parameters. The exponent b describing the shape of the relaxation time spectrum decreases at small values of reduced time, as it does for stress relaxation Discrepancies between calculated and measured densities at 350°C are not resolved by allowing for a nonlinear driving force or thermorheological complexity.