A Study on the Structural Relaxation by the Simultabeous Measurements of enthalpy and Volume under High Pressure

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I have costructed an adiabatic calorimeter which can measure enthalpy and volume of sample simultaneously under high pressure, the method of the enthalpy measurement is similar to that of usual adiabatic calorimeters working at ambient pressure. The cylindrical sample cell is very massive (650 g) and made of copperberyllium alloy to keep the inside pressure. The sample volume can ve obtained by measuring the length of the bellows which is installed inside the cell. A magnet, which is outside the cryostat, is commected to the top of the bellows with a stainless-steel rod. The length of the bellows can be determined by measuring the positon of the magnet with magnet sensors with resolution of 0.1 mum. The temperature and pressure ranges of the calorimeter are 100-375 K and 0-200 MPa, respectively. The temperature and pressure ranges of the temperature measurement is 100 nK and the precision of the pressure control is 1 kPa(0.01 bar).the precision of the heat capacity measurement of the empty cell was 0.02 %. The test measurements for water, which is selected as a standard material, showed excellent accuracy of heat capacity (0.2 %) and volume (1x19^<-5>%). These are accurate enough for the measurements on the structural relaxation.As a preliminary experiment for the simultaneous measurements on the structural relaxation, the enthalpy relaxation of the pressure-jump and temperature-jump glasses of 1-propanol and 3-methylpentane was investigated by using an previous high-pressure calorimeter shich cannot measure volume of sample. from the analysisi on the effective relaxation times, clear difference between the structural relaxations of pressure-jump and temperature-jump glasses was found for the first time.