  We consider the semi-classical dynamics of a free massive scalar field in a
homogeneous and isotropic cosmological spacetime. The scalar field is quantized
using the polymer quantization method assuming that it is described by a
gaussian coherent state. For quadratic potentials, the semi-classical equations
of motion yield a universe that has an early "polymer inflation" phase which is
generic and almost exactly de Sitter, followed by a epoch of slow-roll
inflation. We compute polymer corrections to the slow roll formalism, and
discuss the probability of inflation in this model using a physical Hamiltonian
arising from time gauge fixing. We also show how in this model, it is possible
to obtain a significant amount of slow-roll inflation from sub-Planckain
initial data, hence circumventing some of the criticisms of standard scenarios.
These results show the extent to which a quantum gravity motivated quantization
method affects early universe dynamics.
