RAWSON CRITERION AND INTERMOLECULAR INTERACTIONS IN GLASS-FORMING MELTS

The modification of Rawson's criterion B(M-O)/T(m) (B(M-O) is a single bond strength, T(m) is a melting temperature) into the form EBAR(a)/RT(m) or EBAR(a)/RT(b) (EBAR(a) is the averaged atomization energy, T(m) and T(b) are melting and boiling points) gives an opportunity to analyze all kinds of substances which are divided into three groups: glass-forming, molecular and normal substances. Such an analysis leads to the conclusion that in glass formers there exist special bonds (at least in molten and glassy states) in addition to covalent bonds. Besides that, the self-organization of these bonds into a sub-system is necessary for glass formation. In some respects this sub-system plays a role analogous to that of intermolecular bond sub-systems in molecular substances. The similarity and difference of the two groups of substances and the nature of 'intermolecular' bonds in the case of glass-forming melt are discussed.