On the UV emission during electroluminescence of polyethylene and its implications on the ageing process

Using a very efficient scintillator whose electronic absorption lies in the ultraviolet-near-ultraviolet range, it is shown that excited states in the 5-eV range are created during ageing of polyethylene at a voltage level three times lower than the tree inception voltage. This energy is emitted in the form of luminescence or lost by nonradiative relaxation processes. Both of these can lead to chemical damage. Nonradiative molecular deexcitation channels end in bond breaking, and radiative deexcitation can induce photochemical reactions when chromophores are excited by UV electroluminescence