Corona accelerates the aging of polymers, by generating ozone and UV light. The UV light produced is of short wavelengths and includes the spectra of light damaging to polymers. The electric discharge subjects the insulator to severe electrical strain and chemical degradation. Continued degradation may render the polymer unusable. A polymer must be able to withstand this chemical degradation throughout its service lifetime. Electrical insulation that may be subject to corona must be made from a properly compounded EPR or silicone rubber