Glass transition theory molecular factors

A little work seems to have been carried out on the wavenumber-dependent orientational correlation functions C/m(, t). These correlation functions can provide valuable insight into the details of microscopic dynamics of the system. A molecular level understanding of C/m(, t) would first require the development of a molecular hydrodynamic theory that would have coupling between C/m(, t) and the dynamic structure factor S(k, t) of the liquid. A slowdown in C/m(, t) may drive a slowdown in the dynamic structure factor. This would then give rise to a two-order parameter theory of the type develops by Sjogren in the context of the glass transition and applied to liquid crystals by Li et al. [91]. However, a detailed microscopic derivation of the hydrodynamic equations and their manifestations have not been addressed yet. 

The free-volume theory of the glass transition, as developed in Section 8.6.1, is concerned with the introduction of free volume as a requirement for coordinated molecular motion, leading to reptation.The WLF equation also serves to introduce some kinetic aspects. For example, if the time frame of an experiment is decreased by a factor of 10 near Tg, equations (8.47) and (8.48) indicate that the glass transition temperature should be raised by about 3°C ... 

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