Quench-in of different high T complexities of glassformers for leisurely study at lower temperatures

Quenching-in of different high T complexities of glassformers for leisurely study at lower temperatures We describe a series of experiments on glass-forming liquids that are motivated by a common idea. The idea is that of trapping in a high enthalpy, high entropy, and state of the system by quenching to the glassy state at extreme rates, and then observing the way the system evolves at low temperatures during a controlled annealing procedure. In this manner, events that normally occur during change of temperature may be observed occurring during passage of time, at much lower temperatures. At these low temperatures, the smearing effects of vibrationally excited modes may be greatly reduced. We study both relaxational properties and vibrational properties and find that the high fictive temperature states are characterized by short relaxation times (already known) and considerably more intense boson peaks (less well known) [1]. The thermodynamic consequences of the increased populations of these low frequency modes are examined with the help of computer simulation and normal mode calculations on model glassformers. Behavior in the vibrational DOS at constant pressure is strikingly different from that at constant volume. For glassformers that can exhibit liquid-liquid transitions, one can use the cold equilibration approach to determine the fragility of the high temperature phase, and the enthalpy of the liquid-liquid transition, see ref.2. References. 1. C. A. Angell, Yuanzheng Yue, Limin Wang, John R. D. Copley, Steve Borick and Stefano Mossa. J. Phys. Cond Matt 15, S1051-S1068 (2003) 2. M. C. Wilding, P. F. McMillan, Polyamorphic transitions in yttria-alumina liquids, J. Non-Cryst. Solids 293, 357 (2001).