On the cooperativity of the beta-relaxation: A discussion based on dielectric relaxation and thermally stimulated depolarisation currents data

The idea recently spread in the literature that the beta -relaxation origin ates from cooperative motions in the glassy state is analysed. The results obtained by two different dielectric techniques, dielectric relaxation spec troscopy (DRS) and thermally stimulated depolarisation currents (TSDC), are compared and, from this comparison, it is concluded that: 1, The beta -rel axation is distributed in energy, but not in entropy (i.e. in the pre-expon ential factor). 2, It thus corresponds to local, non-cooperative molecular motional processes. 3, The results obtained by both dielectric techniques c an be rendered compatible if we assume that the nature of the energy distri bution associated with the beta -process is such that the most probable ene rgy is temperature dependent.