  We analyze the onset of classical field configurations after a phase
transition. Firstly, we motivate the problem by means of a toy model in quantum
mechanics. Subsequently, we consider a scalar field theory in which the
system-field interacts with its environment, represented both by further scalar
fields and by its own short-wavelength modes. We show that, for very rapid
quenches, the order parameter can be treated classically by the time that it
has achieved its ground state values (spinodal time).
