Research Of The Glass Transition Of Glycerol-water Solution During Cooling Process By Dielectric Spectroscopy

The cognition of the glass transition from macro to micro was developed and the researchmethods were tent to diversify, but there are still many problems can not be solved. Glycerol istypical of the glass material, so far a variety of methods were studied on glycerol glass transition.Among them, broadband dielectric spectroscopy is one of the commonly used and effectivemethod.Based on dielectric spectroscopy method and the characteristics of the glycerol-watersolution, a set of experiment device was designed, and the corresponding experimental programwas proposed.Selecting method of the dielectric spectroscopy for this article mainly because:1)measurement of band width, the maximum span of18orders of magnitude from10-6Hz to1012Hz.In other words, it can detect the characteristic time of substances from106sec to10-12sec indielectric process;2) secondary audio to the audio band just covers the characteristic time of theglass transition range of material so the glass transition process of material which can be dielectricresponded was typified tend to be extremely effective by the broadband dielectric spectroscopy.Therefore, in this paper dielectric spectroscopy method was applied to the dielectric spectroscopyof glycerol-water solution. It is very meaningful to explore the experimental and analyticalmethods take advantage of this spectroscopic method to study the glass transition. In addition, thepaper select the glycerol-water solution as the research object, the reasons are:1) glycerol iswidely used, especially for the biological preservation of its advantages more prominent;2)glycerol is typical of the glass material while the water is very difficult to crystallize, the purposeto study the coexistence of glycerin and water system is to study the impact of the water inglycerol glass transition, and to explore the microscopic mechanism of the glass transition.The results show that when the concentrations are higher than55%,with increasingproportion of water in glycerol-water solution, from220K to160K cooling temperature region,the glass transition temperature gradually move to the high temperature zone and this phenomenonis related to the plasticizing effect of water. The real and imaginary parts of permittivity occurredobvious inflexion at ratio from5%to50%of glycerol-water solution during cooling process fromroom temperature to200K. This phenomenon is undoubtedly related to the proportion of water.The results showed that the ratio of55%glycerol-water solution as the boundary line, when theconcentrations are higher than55%, the phase transition will not happen, but glycerol-watersolution concentrations are less than55%the phase transition will occur.It is feasible to research on chemical reaction by method of dielectric spectrum, which can beseen from the research work in this paper. While at this stage there are still some unresolved issues,the research methods and analysis in this paper has offered some consultation and basis for deeperresearch in the future.