Complete sets of dissociation cross-sections for the process O + O-2(v)-->3O for different rotational temperatures have been calculated by using a quasi-classical trajectory method, in the range 0.001-3 eV of translational energy. The strategy adopted to reduce as much as possible the huge amount of calculations is described. Globally our results appear in good agreement with respect to thermal experimental data available, with a simple approximate method for treating multiple surface problem, considering dissociated all quasi-bound states. (C) 2002 Elsevier Science B.V. All rights reserved.