Optical hystefwsis in oleic acid and castor oil under pressure

Abstract

Liquid oleic acid and castor oil (at temperature T = 20°C) exhibit a strong scattering in the case when pressures above 0.21 and 0.36 GPa are applied, respectively. The transmitted and scattered light have been viewed at an angle θ = 0° and at an angle θ = 90° respectively to direction of propagation of the incident beam of light at pressures up to 0.9 GPa. Measurements of the intensities of the transmitted and scattered light as a function of increasing and decreasing pressure show phenomenon of the optical hysteresis. The analyses of all hysteresis curves in the case of the slow application of pressure show that returning of oleic acid and castor oil to the original state takes place through the new state which gives further information about the nature of the observed high-pressure states.

Key Words:

• Light scattering
• pressure optical hysteresis
• oleic acid
• castor oil