A RAMAN-STUDY OF B2O3 THROUGH THE LIQUID-GLASS TRANSITION RANGE

The low frequency Raman spectrum of B2O3 and the boroxol ring vibrational mode at 808 cm-1 have been studied from room temperature to 1273K as the glass transforms to a melt. Both the low frequency ''boson'' peak and the boroxol mode are markedly influenced by the glass transition. Raising the temperature above T(g) the strength of the 808 cm-1 mode decreases linearly indicating the similar behavior of the boroxol ring concentration. The boson peak shows a different temperature behavior, which mirrors that of the sound velocity. The structural correlation length demostrates the same correlation range in the liquid and the glass. The results, when compared with neutron diffraction measurements, contradict a recently proposed relation between the ''boson correlation length'' and the position of the first sharp diffraction peak of the structure factor.