  Time dependent perturbations of states in the holographic dual of a 3+1
dimensional confining theory are considered. The perturbations are induced by
varying the coupling to the theory's most relevant operator. The dual
gravitational theory belongs to a class of Einstein-dilaton theories which
exhibit a mass gap at zero temperature and a first order deconfining phase
transition at finite temperature. The perturbation is realized in various
thermal bulk solutions by specifying time dependent boundary conditions on the
scalar, and we solve the fully backreacted Einstein-dilaton equations of motion
subject to these boundary conditions. We compute the characteristic time scale
of many thermalization processes, noting that in every case we examine, this
time scale is determined by the imaginary part of the lowest lying quasi-normal
mode of the final state black brane. We quantify the dependence of this final
state on parameters of the quench, and construct a dynamical phase diagram.
Further support for a universal scaling regime in the abrupt quench limit is
provided.
