INTERPLAY OF ORIENTATIONAL ORDER AND VISCOELASTICITY IN SUPERCOOLED LIQUIDS NEAR THE GLASS-TRANSITION

The problem of the liquid-glass transformation continues to be a challenging one. It has been recently tackled by several high-powered theories such as mode-mode coupling. By contrast, the present model employs the intuitive picture of local orientational order in supercooled liquids and combines this with a variant of the Maxwell model of viscoelasticity. The resulting dynamic theory provides a simple scenario of how the viscosity of a supercooled liquid is enhanced due to its tendency to order orientationally. An important by-product is an expression for the glass-transition temperature in terms of the microscopic parameters of the theory, via which a connection with the formal, spin-glass theoretical approach can be established. The model leads to expressions for the dynamical modes in a supercooled liquid-quantities of direct experimental interest.