Ozone is an extremely reactive form of oxygen occurring around electrical discharges. It is also present in the atmosphere, but in small quantities. Ozone testing is performed to determine the effect on materials such as rubber, plastics, etc, which are susceptible to ozone-induced degradation.
Ozone testing is specified in the following:
MIL-STD-210, ASTM-D-1149, MIL-T-28800