MOLECULAR MOBILITY AND STRUCTURAL STATE RELATIONSHIP IN AMORPHOUS POLYMERS

The dynamics of slow relaxations, alpha and beta, exhibited by an amor phous polymer is studied by means of low-frequency mechanical spectros copy. The complex shear modulus spectra of the material were measured as a function of temperature in the liquid state and at temperature le ss than the glass transition temperature, The effect of structural rel axation in the glassy state was analysed. The alpha relaxation is anal yzed in terms of the magnitude of cooperativity of molecular motions a s a function of structural state, i.e. of disorder. It is shown that c ooperative effects decrease as the disorder increases. (C) 1998 Elsevi er Science B.V. All rights reserved.