  This paper reviews recent Monte Carlo simulation studies of the glassy
behavior in thin polymer films. The simulations employ a version of the
bond-fluctuation lattice model, in which the glass transition is driven by the
competition between a stiffening of the polymers and their dense packing in the
melt. The melt is geometrically confined between two impenetrable walls
separated by distances ranging from once to about fifteen times the bulk radius
of gyration. The confinement influences static and dynamic properties of the
films: Chains close to the wall preferentially orient parallel to it. This
orientation tendency propagates through the film and leads to a layer structure
at low temperatures and small thicknesses. The layer structure strongly
suppresses out-of-plane reorientations of the chains. In-plane reorientations
have to take place in a high density environment which gives rise to an
increase of the corresponding relaxation times. However, local density
fluctuations are enhanced if film thickness and temperature decrease. This
implies a reduction of the glass transition temperature with decreasing film
thickness.
