CORRELATION OF THE GLASS-TRANSITION AND THE PRESSURE-DEPENDENCE OF VISCOSITY IN LIQUIDS

The determination of the glass-transition pressure by the ruby R 1 line-broadening method is quantitatively confirmed to within 10% by an independent method. The procedure utilizes a model which describes the pressure dependence of the viscosity and contains the glass-transition pressure as a parameter. The two methods are compared for three liquids, n-butyl chloride, 4 : 1 methanol-ethanol, and isopropyl alcohol. Data from earlier works are used for 4 : 1 methanol-ethanol and isopropyl alcohol. The viscosity of n-butyl chloride at room temperature is measured as a function of pressure to 36 kbars in a diamond-anvil falling-sphere viscometer, and the glass-transition pressure is determined by a separate measurement using the ruby R1 line-broadening method.