EVIDENCE OF KINETIC EFFECTS IN LIQUID-REVERSIBLE-ARROW-GLASS TRANSITIONS

The Wendt-Abraham criterion [H. R. Wendt and F. F. Abraham, Phys. Rev. Lett. 41,1244 (1978)] is reexamined using computer simulations with a n intention to study the kinetic effect in the liquid half arrow right over half arrow left glass transitions. This was carried out by heati ng an as-quenched glassy metal potassium via (i) a Monte Carlo simulat ion, which presumably is at an infinite heating rate, and (ii) a molec ular-dynamics simulation, which was monitored to run from a finitely h igh to a lower heating rate. It was found that when the system is heat ed at a rapid heating rate (relative to cooling), structural relaxatio n was observed to delay, resulting in an almost linear change in the W endt-Abraham parameter versus temperature relationship. This delay in structural relaxation was characterized also by virtually unchanged pa ir-correlation functions for both quenching and heating processes at v arious temperatures. On the other hand, at a lower heating rate, when the experimental time scale is approaching the average relaxation time , the system undergoes a structural relaxation displaying an anomalous change in the Wendt-Abraham parameter with temperature. In this case structural relaxation was accompanied also by a more orderly structure . These latter behaviors are quite similar to previously related exper iments and their interrelation will be discussed in text.