Using optoacoustic spectroscopy, the radiationless decay processes of intramolecular exciplexes of w-phenyl-aN, N-dimethylaminoalkanes are investigated. Upon increase of the solvent polarity, the relative efficiency of the intersystem crossing process from the singlet exciplex to the locally excited triplet decreases compared to the efficiency of the internal conversion process. These results can be rationalized in the framework of the current ...