The photoreduction of anthraquinone in the ethylene glycol/Triton micelle and ethylene glycol/triethylamine solution was studied with the time resolved electron spin resonance (TR-ESR) spectroscopy. The very strong TR-ESR signal of the semianthraquinone radical AQH^•, formed from the hydrogen transfer from Triton X to ³AQ, was recorded in the ethylene glycol/Triton micelle, and the TR-ESR signal of the anthraquinone anion radical AQ^•－ was also detected in this micelle system. The significant TR-ESR signals of semianthraquinone radical AQH^• and anthraquinone anion radical AQ^•－ were obtained simultaneously in the anthraquinone/ethylene glycol/triethylamine system through two separate paths. The semianthraquinone radical AQH^• was generated through hydrogen transfer reaction from triethylamine, while anthraquinone anion radical AQ^•－ was produced through electron transfer reaction and the triethylamine was the donor. Based on the experimental results mentioned above, the photoreduction processes of anthraquinone in these two systems were analyzed in detail. At the same time, the reaction rate constants of the triplet ³AQ^* to radical AQH^• were deduced according to the dependence of CIDEP (chemically induced dynamic electron polarization) intensity on the concentration of Triton X and triethylamine. Furthermore, the relaxation time of radical AQH^• was also calculated from its time dependent CIDEP signal.

Key words: chemically induced dynamic electron polarization, semianthraquinone radical, anthraquinone anion radical, triethylamine, surfactant