We describe the dynamical behavior found in numerical solutions of the Vect
or Complex Ginzburg-Landau equation in parameter values where plane waves a
re stable. Topological defects in the system are responsible for a rich beh
avior. At low coupling between the vector components, a frozen phase is fou
nd, whereas a gas-like phase appears at higher coupling. The transition is
a consequence of a defect unbinding phenomena. Entropy functions display a
characteristic behavior around the transition. (C) 1999 Published by Elsevi
er Science B.V. All rights reserved.