The Photosensitising Properties and Photostability of Stilbene Fluorescent Whitening Agents

Several stilbenes have been shown to sensitise the formation of singlet oxygen, which is capable of oxidising indole residues, e.g. tryptophan. Some stilbenes were found to quench singlet oxygen, e.g. disodium 4,4′-diaminostilbene-2,2′-disulphonate. Such materials have been shown to be capable of sensitising the photoyellowing of wool and proved to be no more stable than conventional stilbene fluorescent whitening agents (FWAs)