Dynamics of confined glass-forming systems observed by neutron scattering

In this article, results on the microscopic dynamics of a low-molecular glass former and a polymer confined in nanoporous silica obtained by inelastic neutron scattering are presented. By combining time-of-flight spectroscopy and backscattering spectroscopy we are able to cover a large dynamical range, from the low-frequency vibrations to the α relaxation. The most prominent effect was observed on the 'boson peak' in the vibrational spectrum. A strong reduction of the modes at lowest frequencies could be observed in both cases. The main effect on the α relaxation is a broadening for the salol system. For the polymeric system a difference of the confinement influence on the methyl-group rotation and the α relaxation can be detected from a first qualitative interpretation of the data