Orientational dynamics in supercooled liquids near Tc and comparison with ideal mode-coupling theory

Orientational dynamics in supercooled salol and ortho-terphenyl were measured near their critical temperatures, T-c, with optical Kerr effect experiments spanning a very broad range of times. Above T-c, the decays are shown to be in excellent agreement with the master curve predicted by ideal mode-coupling theory when higher order terms are included. Between the critical decay and the von Schweidler power laws, the intermediate time range of the data can be modeled by a power law. This intermediate power law, located at 2 < t < 10 ps to 500 ps (depending on temperature), shows a significant temperature dependence with a power law exponent of similar to-1 below T-c.