Pm. Mehl, THE ISOTHERMAL RELAXATION OF THE GLASSY STATE OF 60-PERCENT W W ETHYLENE-GLYCOL IN WATER - A POSSIBLE NUCLEATION PROCESS BELOW THE GLASS-TRANSITION/, Thermochimica acta, 226, 1993, pp. 27-32
Calorimetric measurements with or without annealing around the glass t
ransition were performed for the aqueous solution of 60% w/w ethylene
glycol. Excess entropies and excess enthalpies were calculated as func
tions of annealing times and temperatures. The kinetics of the relaxat
ion was analyzed and shows that relaxation does not reach completion o
ver experimental time. Therefore, another phenomenon and the relaxatio
n of the glassy state are overlapping. This phenomenon is assumed to b
e a nucleation process. The kinetics parameters are, however, determin
ed under isothermal conditions in the range of annealing times and tem
peratures were the nucleation is still suppressed. Slower warming rate
s that allow crystal growth show increased crystallization with anneal
ing time which supports the hypothesis of nucleus formation during ann
ealing.