  Orientational relaxation (OR) in a viscous, glassy liquid is investigated by
carrying out extensive NPT molecular dynamics simulations of isolated
ellipsoids in a glass forming binary mixture.
  Near the glass transition, the OR occurs mainly via hopping involving either
a ring- or a tunnel like motion, with the participation of several neighboring
atoms. In the glassy state, hopping is found to be accompanied by larger
fluctuations in the total energy and the volume of the system. Both
orientational and translational hopping are found to be {\it gated}, restricted
primarily by the entropic bottlenecks, with orientation becoming increasingly
slower than translation as the pressure is increased. OR is heterogeneous, with
a wide distribution of decay times.
