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.
We study the dynamic behavior of marginal metallic glass-forming liquids Al-Ni-M （M=La, Pr, Nd） in terms of liquid fragility in high and low temperature regions. The liquids are extremely fragile above the liquidus temperature T liq, but become rather strong near the glass transition temperature Tg. The strength of the transition is inversely correlated with the fragility index at Tg. This relation is discussed in terms of potential energy landscape.
