HIGH-PRESSURE VISCOSITY OF GLASS-FORMING LIQUIDS MEASURED BY THE CENTRIFUGAL FORCE DIAMOND ANVIL CELL VISCOMETER

The development and use of the centrifugal force diamond anvil cell viscometer described here extends the range of continuous high-pressure viscosity measurements on a single sample to greater than 10(9) cP at pressures which can exceed 10 GPa. Measurement of the high-pressure viscosity of the common glass-forming liquids glycerol, 1,2-propanediol, methanol, and dibutyl phthalate over extreme compression ranges demonstrates the accuracy of the technique. A simple free volume model fits these data remarkably well over 9 decades in viscosity and at compressions of up to 44%. Extrapolation of this data leads to estimated glass transition pressures in good agreement with independent experimental determinations.