Relationship between dynamics and thermodynamics in glass-forming polymers

We have tested the validity of the Adam-Gibbs (AG) equation to glass-forming polymers by means of dynamics data from dielectric relaxation and thermodynamic data. The AG equation holds for polymers with simple monomeric chemical structure, whereas it seems to fails for more complex systems possessing secondary relaxation processes with some degree of intra-chain cooperativity. However, we found that the AG equation still works once the contribution to the excess entropy of intra-chain secondary relaxation processes uncoupled to the α process is removed. This contribution results to be essentially temperature independent.