With pulse radiolysis and detection by optical absorption spectroscopy in transparent, molten and highly viscous PE doped with aromatic olefins as styrene, 1-methylstyrene, 1,1′-diphenylethylene and tetraphenylethylene radical and ionic transients of these scavengers were observed. From the rapid formation behaviour of the benzyl type radicals a mechanism is concluded consisting in a fast motion of excitation energy along the polymer chain with a subsequent trapping by foreign molecules under direct dissociation into radicals. Because of the PE parent cation fragmentation ionic species derived from the aromatic olefins were generated only at scavenger concentrations of ≧ 10−2mol dm−3.