Structural Relaxation Under Conditions Far From Equilibrium

Enthalpy relaxation has been studied in slowly cooled bulk (near equilibrium) and in rapidly cooled thin fiber (far from equlibrium) samples of a mixed and a single alkali glass of equivalent compositions. In both glasses, while the relaxation in bulk samples can be well described by the Tool-Narayanaswamy model, the model fails in the case of fibers. It is demonstrated that the anomalous behaviour of fibers is not because of a change in the composition of the fiber samples compared to the bulk samples, and is not a manifestation of the mixed alkali effect.