Glass .fwdarw. Liquid Transition and Devitrification of LiCl.cntdot.11H2O Solution and of Hyperquenched and Vapor-Deposited Water

Calorimetric study of water's two glass transitions in the presence of LiCl

“…The change in heat capacity increases much more with salt content, and it reaches about 70 J mol –1 K –1 at x = 0.103. Mayer et al reported Δ c p ≫ 20 J mol –1 K –1 for a hyperquenched solution with x = 0.083, 50 in good agreement with the results of Fig. 8c .…”

Structural Relaxation and H Bonding in Isomeric Octanols and Their LiCl Solutions by Calorimetry

“…This approach toward a minimum value has been attributed to plasticization of the water's network structure in the same manner as the plasticization of the SiO 2 network structure by the presence of ions . For 5.3 mol % LiCl solution in water (Figure in refs and ), Δ C p is nearly 3 times as high 38 as for pure hyperquenched glassy water. , For 8.33 mol % LiCl solution, which was virtrified by the usual slow cooling in Mayer et al's study, Δ C p increased to nearly 11 times the value for the hyperquenched glassy water, , while T g increased by 2 K and the temperature width of the T g endotherm decreased 38 to less than half the value for hyperquenched glassy water. , In the present study, the effects of LiCl on both the T g and Δ C p have been found to depend upon the type of intermolecularly associated H-bonded motifs in the isomeric alcohols, which shows that the effects of ions on the configurational thermodynamics of a liquid depend upon the structure of the liquid itself and on any ion-solvent interactions and ion−ion interactions in it. That is, a liquid acting as a solvent no longer has the same structure as in the pure state and any distribution of its structural relaxation times is modified by the presence of ions, in a manner that depends upon the structure of the pure liquid itself.…”

“…We conclude that changes in the configurational thermodynamics caused by the presence of ions should be considered also in relations to ion−solvent interactions. It is worth pointing out that these interactions also alter the crystallization kinetics of the solvent, as Mayer et al have discussed. This in turn means that direct comparisons of the crystallization kinetics of a pure liquid and it acting as a solvent, as done for water and LiCl solution by Angell, can be misleading.…”

Sudden switchover between the polyamorphic phase separation and the glass-to-liquid transition in glassy LiCl aqueous solutions

“…We know that the homogeneous vitrification of LiClaq solutions depends strongly on the preparation conditions, for example, the cooling rate and the pressure. 7,23,24,[26][27][28] Actually, it is possible to vitrify the pure water and the very dilute LiClaq solution at 1 atm using a liquid-hyperquenching method with a cooling rate of ∼10 6 K/s. 7,26,27 Previously, we vitrified the dilute LiClaq solutions at 1 atm using the liquid-hyperquenching method and examined their solvent state using Raman spectroscopy.…”

“…7,23,24,[26][27][28] Actually, it is possible to vitrify the pure water and the very dilute LiClaq solution at 1 atm using a liquid-hyperquenching method with a cooling rate of ∼10 6 K/s. 7,26,27 Previously, we vitrified the dilute LiClaq solutions at 1 atm using the liquid-hyperquenching method and examined their solvent state using Raman spectroscopy. 7 We suggested that the glassy dilute LiClaq solution is the inhomogeneous glass in which the low-density amorphous ice (LDA) and the glassy highly concentrated LiClaq solutions coexist.…”