  We consider model A dynamics for a quench from the disordered into the
ordered phase of SU(3) lattice gauge theory and the analogue 3d 3-state Potts
model. For the gauge model this corresponds to a rapid heating from the
confined to the deconfined phase. The exponential growth factors of low-lying
structure function modes are numerically calculated. The linear theory of
spinodal decomposition is used to determine the critical modes. This allows for
the Debye screening mass estimation in an effective phenomenological model. The
quench leads to competing vacuum domains, which make the equilibration of the
QCD vacuum after the heating non-trivial. The influence of such domains on the
gluonic energy density is studied.
