  We demonstrate how to match pre-equilibrium dynamics of a 0+1 dimensional
quark gluon plasma to 2nd-order viscous hydrodynamical evolution. The matching
allows us to specify the initial values of the energy density and shear tensor
at the initial time of hydrodynamical evolution as a function of the lifetime
of the pre-equilibrium period. We compare two models for the pre-equilibrium
quark-gluon plasma, longitudinal free streaming and collisionally-broadened
longitudinal expansion, and present analytic formulas which can be used to fix
the necessary components of the energy-momentum tensor. The resulting dynamical
models can be used to assess the effect of pre-equilibrium dynamics on
quark-gluon plasma observables. Additionally, we investigate the dependence of
entropy production on pre-equilibrium dynamics and discuss the limitations of
the standard definitions of the non-equilibrium entropy.
