Published Date2019-08-01
JournalPhysical review. E, 2019-08-01, Volume 100 Find other publications in this journal
Author Info
  • Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
  • Department of Physics, Saint Joseph's University, Philadelphia, Pennsylvania 19131, USA.
  • Department of Physics and Engineering, West Chester University, West Chester, Pennsylvania 19383, USA.


Spatiotemporal dynamics of short- and long-time structural relaxation are measured experimentally as a function of packing fraction, ϕ, in quasi-two-dimensional colloidal supercooled liquids and glasses. The relaxation times associated with long-time dynamic heterogeneity and short-time intracage motion are found to be strongly correlated and to grow by orders of magnitude with increasing ϕ toward dynamic arrest. We find that clusters of fast particles on the two timescales often overlap, and, interestingly, the distribution of minimum-spatial-separation between closest nonoverlapping clusters across the two timescales is revealed to be exponential with a decay length that increases with ϕ. In total, the experimental observations suggest short-time relaxation events are very often precursors to heterogeneous relaxation at longer timescales in glassy materials.