Excitation spectra of the triplet states of some model lignin compounds

The triplet state excitation spectra of a number of model lignin compounds have been determined by measurements of the electron spin resonance signals associated with their triplet states in low-temperature glasses at 110 K. The optimum wavelengths for excitation of these triplet states were found to be in the tail of the main absorption band at 320-340 nm. It is postulated that excitation in the main band is inefficient in producing triplet states because of an alternative pathway for energy degradation.