LIGHT-SCATTERING SPECTROSCOPY OF THE LIQUID-GLASS TRANSITION

Supercooled liquids approaching the liquid-glass transition exhibit un usual properties associated with structural relaxation. The mode-couPl ing theory (MCT) of supercooled liquid dynamics shows that non-linear interactions among density fluctuation modes can produce effects resem bling these observations. MCT produces detailed predictions for the dy namics of density fluctuations in supercooled liquids, including a cro ssover from liquid to glassy dynamics at a critical temperature T(c). Recent light scattering studies of supercooled CaKNO3 are described th at have provided detailed tests of MCT both above and below T(c), incl uding a cusp in the scaling time at T(c) = 105 +/- 5-degrees-C. These experiments are reviewed, and comparisons with both the idealized and extended versions of MCT are described.