Fragility in side-chain liquid crystalline polymers: the TSDC contribution

In the present work a procedure is proposed to obtain the fragility of a gl ass from Thermally Stimulated Depolarisation Currents (TSDC) data. From pre vious TSDC studies on wide series side-chain liquid crystalline polymers, a nd particularly from a careful thermal sampling analysis of their glass tra nsition relaxation, the fragility parameter was obtained. The proposed frag ility scale is based on the concept of deviation from the zero entropy pred iction, and is such that zero is the limit of fragility for infinitely stro ng glasses. The fragility of 10 side chain liquid crystalline polymers is d iscussed in terms of their molecular structure. (C) 2000 Elsevier Science L td. All rights reserved.