Abstract
The ionic liquids , 1-buthyl-3-methylimidazolium chloride ([bmim]Cl) and 1-ethyl-3-methylimidazolium chloride ([emim]Cl) aqueous solutions are studied by the measurement of refractive index and micro-Brillouin scattering spectroscopy. Temperature dependence of refractive index of [bmim]Cl and [emim]Cl aqueous solutions at 532 nm is determined. The glass transition temperature is determined by the change of sound velocity. The [bmim]Cl and [emim]Cl aqueous solutions show a typical structural relaxation, and undergo a liquid-glass transition at low temperatures. Our results verify that the glass transition behavior of ionic liquids is similar to typical cryoprotectants such as glycerol.
