Neutron spin echo investigations in the α and β relaxation regime of polybutadiene

This short review presents quasielastic neutron scattering and dielectric experiments on the α and β slow relaxation in polybutadiene. Exploiting the momentum transfer dependent dynamic structure factor, spatial information about the underlying molecular motions is obtained. While the β slow process reveals itself as a local jump with average jump distances of about 1.5 Å, the α relaxation is diffusive and occurs statistically independently from the β slow process. With this result a consistent interpretation of dielectric spectra on the same polymer is achieved.