Vitrified dilute aqueous solutions. 4. Effects of electrolytes and polyhydric alcohols on the glass transition features of hyperquenched aqueous solutions

Glass transition and crystallization of water and aqueous solutions of organic liquids

“…However, the values of T g obtained in these investigations cover a wide temperature range, from values comparable with the results of direct measurements, 136 ± 1 K [7,8] , to those that exceed them considerably, 160-165 K [9]. An analysis of the concentration dependences of T g for rapidly quenched aqueous solutions of polyhydric alcohols in a wide concentration range [10] with allowance for the data obtained for hyperquenched droplets in the range of low values of the dissolved substance content [11] has shown that such an extrapolation does not take into account possible anomalies in the behavior of the plots of T g versus concentration, which are connected with the structural peculiarities of water and may lead to considerable errors in determining the glass transition temperature of pure water.…”

Response to ‘‘Comment on ‘The effect of charged impurities on a glass transition in a polar medium’ ’’ [J. Chem. Phys. 105, 8979 (1996)]

“…However, in recent experiments a substantial dependence on the ion size has been observed. 5,6 As pointed out by Miller, de Pablo, and Corti ͑MPC͒ in Ref. 7, these experiments appear to contradict the theory presented in Ref.…”

“…The discrepancy between predictions of the DL theory and the experimental data 5,6 might be due to additional physical processes taking place in supercooled solvents. For example, the initial decrease of T g on the concentration of salt perhaps is connected with hindering dissociation of the neutral salt molecules into ions by coagulation and condensation of the aggregates ͑we point out that the authors of Refs.…”

“…In some cases the transition temperature has a maximum, 4 in other cases a minimum. 5,6 Due to the long-range nature of the interaction between ions and glassy dipoles, the glass transition temperature is expected to be weakly dependent on the ion radius ͑see Fig. 3 of Ref.…”

“…7, experiments contradict this conclusion. 5,6 There are several possible reasons for this which arise from features not considered in the DL theory. First, it is unclear whether the geometrical size of ions is more important than aggregation and dissociation properties of different salt molecules.…”