  We study the phase-ordering of parametrically and incoherently driven
microcavity polaritons after an infinitely rapid quench across the critical
region. We confirm that the system, despite its driven-dissipative nature,
fulfils dynamical scaling hypothesis for both driving schemes by exhibiting
self-similar patterns for the two-point correlator at late times of the phase
ordering. We show that polaritons are characterised by the dynamical critical
exponent z ~ 2 with topological defects playing a fundamental role in the
dynamics, giving logarithmic corrections both to the power-law decay of the
number of vortices and to the associated growth of the characteristic
length-scale.
