Ionic and excited species in irradiated poly(vinyl chloride) doped with aromatic admixtures: low temperature studies

摘要

The influence of temperature (77-290 K) on the fate of dopant radical ions and respective excited states in irradiated poly(vinyl chloride) (PVC) matrix doped with pyrene, (Py) and tris(2-ethylhexyl) trimellitate (TOTM) is described. At 77 K dopant radical ions start to recombine via tunneling charge transfer, leading to weak isothermal luminescence (ITL). The wavelength-selected radiothermoluminescence (WS RTL) broad maxima observed for doped PVC in the temperature range 95-110 K have a similar origin, i.e., recombination of dopant radical ions via tunneling. Apart from the peaks representing the absorption of dopant radical ions the absorption maximum at 411 nm found for the PVC-Py system is attributed to Py-Cl adduct generated in Py center dot+ + Cl- reaction. The mechanisms involved in these processes are discussed.