The vibrational relaxation processes occurring during collisions of vibrationally excited O-2 and OH are investigated using the quasiclassical trajectory method and a realistic double many-body expansion (DMBEI) potential energy surface for ground-state HO3. A salient feature is the observation of multiquanta deactivation processes for such high internal energies. It is also shown that the vibrational relaxation of colliding molecules is far less important than the reactive processes leading to formation of "odd-oxygen" (and hence ozone) under stratospheric local thermodynamic disequilibrium conditions.