Temperature dependence of the dynamic scattering function in glycerol studied by quasi-elastic slow neutron scattering

Microscopic dynamics of glycerol across the liquid–glass transition has been studied by incoherent slow neutron scattering performed at temperatures from 400 K to 50 K. The experimental data are analyzed in terms of the dynamic scattering function S(Q,hν) and the generalized frequency distribution G(hν). The well-resolved peak observed at low frequencies is referred to as the boson peak, and its position does not depend on the scattering angle but varies as a function of temperature within the range 3.5–5 meV. This peak proves a soft dynamics additionally to the acoustic modes. On the other hand, the quasi-elastic line does not depend on Q but shows a non-monotonic temperature dependence, which could support the idea of a two-step process taking place at the glass transition. OH proton in the hydrogen bond.