A new threshold of uncovering the nature of glass transition: The slow β relaxation in glassy states

The glass transition involves more than one dynamic relaxation mechanisms in supercooled liquids, such as α relaxation, slow β relaxation and fast β relaxation and so on. For the traditional theoretical system, α relaxation is believed mainly responsible for the nature of the glass transition as the beginning of the phenomenon. This idea, however, has been open to a big challenge since recent studies have indicated that slow β relaxation closely relates to α relaxation. Slow β relaxation determines the characteristics of α relaxation and is the precursor and the more microscopic base of glass transition behavior. In order to illuminate the significance of slow β relaxation in the fields of the glass transition and the structure of supercooled liquids, the accomplished progress is summarized from different aspects such as on the correlation between α relaxation and slow β relaxation, on the manner of α-slow β relaxation merging, on the energy landscape, on the excess wing and on the thermodynamically phenomenological models. The tendency of investigation in slow β relaxation is also evaluated. © 2009 Science in China Press and Springer Berlin Heidelberg.