Glass-transition temperature: Relation between low-frequency dynamics and medium-range order

Several glass samples taken from one batch and stabilized at different temperatures Tf in the glass-transition range are studied by Brillouin and Raman scattering. We obtain evidence for variations with Tf of the profile of the boson peak (BP). The first sharp diffraction peak (FSDP) observed on the same samples with x-rays shows that the two features, BP and FSDP, are not clearly correlated. The results support the idea that the onset of the BP is connected with the high-frequency acoustic phonon damping.