THE BOSON PEAK IN GLASS FORMERS OF INCREASING FRAGILITY

The 'universal' low frequency vibrational behaviour of glasses has bee n investigated for systems of increased fragility. A dynamical correla tion length, l(c), was determined from the position of the boson peak in low frequency Raman spectra. It is found that the value of l(c) cor relates with the fragility, hence with the relaxation dynamics which c haracterise the system in the liquid-glass transition range. Results f or oxide, ionic and molecular glasses show that l(c) decreases as the fragility of the system increases.