Abstract
The ac nonlinear dielectric response of glycerol was measured close to its glass transition temperature to investigate the prediction that supercooled liquids respond in an increasingly nonlinear way as the dynamics slows down (as spin glasses do). We find that indeed displays several nontrivial features. It is peaked as a function of the frequency and obeys scaling as a function of , with the relaxation time of the liquid. The height of the peak, proportional to the number of dynamically correlated molecules , increases as the system becomes glassy, and decays as a power law of over several decades beyond the peak. These findings confirm the collective nature of the glassy dynamics and provide the first direct estimate of the dependence of .
- Received 15 January 2010
DOI:https://doi.org/10.1103/PhysRevLett.104.165703
©2010 American Physical Society