GLASS-TRANSITION IN VISCOUS CRUDE OILS UNDER PRESSURE

The transitions to the glassy state in viscous crude oils have been in vestigated at high pressures by the transient hot-wire method, by diff erential scanning calorimetry, and by equation-of-state measurements. The range of pressures investigated was up to 1.2 GPa in the temperatu re interval 150-370 K. The glass transition in crude oils is a common phenomenon and occurs due to the viscosity increase on decreasing the temperature or increasing the pressure. The actual transition coordina tes depend not only on physical properties but also on the characteris tic experimental time.