  We study the phenomenon of self-assembly of silica micro-spheres on a glass
plate during evaporation of the solvent from a colloidal suspension. Our
experiments unveil an interesting competition between ordering and compaction
in a strongly driven, out of equilibrium system arising from a slowing down of
dynamics due to an impending glass transition. A suitable choice of
experimental conditions minimizing the influence of many other competing
phenomena that usually complicate probing of this underlying physics is crucial
for our study. A re-entrant behavior in the order-disorder phase diagram as a
function of particle density and drying time is established and the results are
explained with the help of simulations and phenomenological theory.
