Relationship between dynamics and thermodynamics in glass-forming polymersD. Cangialosi1, A. Alegría2 and J. Colmenero1, 2
1 Fundación Donostia International Physics Center Paseo Manuel de Lardizabal 4, 20018 San Sebastián, Spain
2 Departamento de Física de Materiales, Universidad del País Vasco (UPV/EHU) y Unidad de Física de Materiales Centro Mixto (CSIC-UPV/EHU), Facultad de Química Apartado 1072, 20080 San Sebastián, Spain
received 28 January 2005; accepted in final form 8 April 2005
published online 27 April 2005
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 process is removed. This contribution results to be essentially temperature independent.
61.41.+e - Polymers, elastomers, and plastics.
64.70.Pf - Glass transitions.
61.43.Fs - Glasses.
© EDP Sciences 2005