Effects Of Chromophore Conjugation Length And Concentration On The Photostability Of Indline-Based Nonlinear Optical Chromophore/Polymer Films

Photostability measurements were made on host-guest thin films containing nonlinear optical chromophores with an indoline donor and amorphous polycarbonate. We find that the indoline-based chromophores are nearly 10 times more photostable than an analogous compound previously studied and which has a dihydopyridine donor. There is an enhancement of the photostability with increasing chromophore concentration and conjugation length. This can be attributed to a reduction in the average separation between the chromophores and excited state singlet energy transfer to adjacent chromophores followed by eventual nonradiative decay. This leads to a reduction in the singlet oxygen generation rate as the chromophore concentration or conjugation length is increased.