We have studied the nonlinear dielectric behavior of a glass-forming liquid, d-sorbitol, with particular attention to its exceptionally intense Johari-Goldstein (JG) type secondary relaxation. It is found that this β-relaxation displays significant nonlinear dielectric effects, but these differ qualitatively from their α-process counterparts. High fields increase the amplitudes of the secondary modes (rather than reducing their time constants), consistent with a field induced increase of fictive temperatures. This result implies that the amplitudes of the secondary modes fluctuate in the glassy state, consistent with MD simulations reported for a liquid displaying a JG relaxation. The nonlinear features of this secondary process are reminiscent of those found for the excess wing regime, suggesting that these two contributions to dynamics have common origins. (Graph Presented).
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Materials Chemistry
- Surfaces, Coatings and Films