Experimental Studies of the Liquid-Glass Transition

Cuny City College, New York NY

Investigators

Abstract

This condensed matter physics project entails light-scattering techniques to investigate the molecular glassforming material Salol. The experiments will determine the effects of coupling between molecular translational and orientational dynamics. The results will test theoretical analysis of Pick, Franosch and their coworkers that predicts how the coupling should modify both the transverse and longitudinal dynamics. This investigation will also explore some predictions of the recently developed molecular "mode coupling" theory. A new study of the glass transition in sugars will be pursued, beginning with galactose and trehalose. Such sugars are of considerable interest in food science where the glass transition occurs frequently, but very few studies of dynamics have been reported. These studies will be carried out in collaboration with co-workers at Pusan National University in Korea, whose dielectric and calorimetric studies will complement the Raman, Brillouin, and Photon Correlation spectroscopy performed in the PI's laboratory. The broader importance of this research lies in the widespread application of glassy materials and the importance of understanding the microscopic processes driving the glass transition in order to develop improved material processing procedures. Graduate students are being trained in the use of state-of-the-art light-scattering techniques that are applicable to a wide range of materials and properties. In this condensed matter physics project, the properties of liquids approaching the liquid-glass transition will be studied with a combination of laser light-scattering techniques. Because glassy materials are used in a wide range of applications including fiber optics and plastics, it is important to increase our understanding of the microscopic processes driving the glass transition in order to develop improved material processing procedures. These studies will explore several new effects and will provide detailed tests of new theoretical predictions. A related study will be carried out on the glass transition in sugars, which are of considerable interest in food science. There the glass transition occurs frequently, but very few studies of the dynamics have ever been carried out. The project will train graduate students in the use of state-of-the-art light-scattering techniques that are applicable to a wide range of materials and their properties. These students will be prepared for careers in the academic world, government or industrial laboratories.