Glass transition Adam-Gibbs model

The square tiling model has some attractive features reminiscent of real glasses, such as cooperativity, a relaxation spectrum that can be fit by the KWW equation, and a non-Arrhenius temperature-dependence of the longest relaxation time (Fredrickson 1988). However, the existence of an underlying first-order phase transition in real glasses is doubtful, and the characteristic relaxation time of the tiling model fails to satisfy the Adam-Gibbs equation. 

The entropy theory of the glass transition was developed by Gibbs and DiMarzio and by Adams and Gibbs to describe polymeric systems. By mixing the polymer links with holes or missing sites on a lattice to account for thermal expansion as in a lattice gas model, they could determine the entropy of mixing and the configurational entropy of the polymer. They found a second-order transition at a temperature They then pointed... 

Unlike simple molecules, polymers have a distribution of relaxation times. This non-exponential nature of the relaxation functions of polymers has led to the development of many theories to model their behavior, especially near the glass transition. In 1965, Adam and Gibbs stated that polymer relaxations occur via groups of molecules which rearrange cooperatively. This idea of cooperative relaxation was an important move towards defining the role of polymer interaction in relaxation phenomena. 

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