ENTHALPY RELAXATION OF GLASSY GLYCEROL PREPARED BY RAPID LIQUID QUENCHING

We have studied the enthalpy relaxation of glassy glycerol prepared by quenching of the liquid in a top-loading type adiabatic calorimeter d eveloped by our group. The glassy sample was prepared by plunging the sample cell into liquid nitrogen. The cooling rate, 5 K s(-1), was abo ut 100 times faster than the rate available in ordinary adiabatic calo rimeters. The heat capacity of the rapidly quenched glass (RQG) was on ly slightly different from that of the normally quenched glass (NQG). RQG released much larger enthalpy than NQG and the relaxations started at a much lower temperature than the glass transition temperatures of NQG. We analyzed these data in terms of the Adam-Gibbs theory. We dem onstrate that the relaxation is accelerated by the larger configuratio nal entropy (prominent structural disorder). (C) 1998 Elsevier Science B.V. All rights reserved.