Test of a year-annealed glass for the cohen-grest percolation transition

The first order transition recently postulated by Cohen and Grest to lie somewhere between the normal glass transition temperature T_g and the so-called "ideal glass" transition temperature T_o. will be difficult to observe if it exists because of the long relaxation times needed for any structural changes in this temperature regime. We have recently identified a system in which the possibility for such a transition occurring would seem unsually high. The glass Ag₇I₄AsO₄ has a structural relaxation function such that it equilibrates at room temperature, 40 K below T_g, in a matter of weeks. Samples of this glass which have lain in an equilibrium state 40 K below T_g for a year or more have been characterized thermally to examine the possibility that a first order transition has occurred. The conclusion is that despite the favorable circumtances of the case, and the large thermal spike observed on reheating the annealed glass, nothing unaccounted for by normal annealing processes has occurred.