Length Scale of Cooperativity in the Dynamic Glass Transition

The molecular dynamics in the glass transition of the ``quasi''--van der Waals glass salol confined to nanopores (2.5, 5.0, and 7.5 nm) with lubricated inner surfaces is found to be faster (by up to 2 orders of magnitude) than in the bulk liquid. This effect of confinement is more pronounced for smaller pores. It reflects the cooperativity of molecular motions in the glass transition and enables its length scale to be determined quantitatively.