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

摘要

Lithium chloride aqueous solutions (LiClaq solutions) below 10 mol% are vitrified by cooling from room temperature to 77 K at 0.3 GPa. We examine the solvent state of the glassy sample and its transformation by heating at 1 atm using low-temperature differential scanning calorimetry and Raman spectroscopy. This experimental study suggests strongly that the solvent state of the glassy LiClaq solution closely relates to the state of high-density amorphous ice. Moreover, we reconfirm that the separation into the low-density amorphous ice and the glassy highly concentrated LiClaq solution occurs in the glassy dilute LiClaq solution at ～130 K, not the glass-to-liquid transition which is commonly observed in the glassy LiClaq solution above ～10 mol%. In order to interpret the sudden switchover between the glass-to-liquid transition and the phase separation at ～10 mol%, we propose a state diagram of LiClaq solution which connects with a polyamorphic state diagram of pure water and discuss a possibility that the electric field induces a polyamorphic transition of water.