LOCAL STRUCTURES AND STRUCTURAL RELAXATION PROCESSES IN SUPERCOOLED TETRA(ETHYLENE GLYCOL)

Raman spectra of tetra(ethylene glycol) have been measured at near the glass transition temperature, T-g. The spectra from 750 to 950 cm(-1) indicate that the conformation in the liquid state depends upon tempe rature and may approach to that in the crystalline state with decreasi ng temperature down to T-g. A broad peak known as a boson peak is obse rved at below 233 K in the low-frequency spectra. The lineshape of the boson peak is reproduced by the extended disorder-induced scattering model and structural correlation length is estimated. The correlation between the local structures of molecules and the structural relaxatio n processes obtained by sound velocity and dielectric measurements are discussed.