Two relativistic models for collapsing spheres at different stages of
evolution, which include pre-relaxation processes, are presented. The
influence of relaxation time on the outcome of evolution in both cases
is exhibited and established. It is shown that relaxation processes c
an drastically change the final state of the collapsing system. In par
ticular, there are cases in which the value of the relaxation time det
ermines the bounce or the collapse of the sphere.