  We present numerical simulations for the evolution of an expanding system of
massless scalar fields with quartic coupling. By setting a rotating,
non-isotropic initial configuration, we compute the energy density, the
transverse and longitudinal pressures and the angular momentum of the system.
We compare the time scales associated with the isotropization and the decay of
the initial angular momentum due to the expansion, and show that even for
fairly large initial angular momentum, it decays significantly faster than the
pressure anisotropy.
