  We report the first large scale molecular dynamics simulations of the effect
of the photoisomerization of probe molecules on the dynamics of a glassy
molecular material. We show that the photoisomerization of the probe molecules
induces the creation of an artificial dynamical heterogeneity inside the
matrix. We then study the modification of the dynamics and find, in agreement
with recent experiments, an important increase of the diffusion leading to
liquid like diffusion below the glass transition temperature. We find that the
photoisomerization process controls the heterogeneity and the non-Gaussian
parameter of the material, leading to extremely rapid variations of these
quantities.
