Disclosed is a colorant composition of the formula ##STR00001## wherein R is an alkyl group, an aryl group, an arylalkyl group, or an alkylaryl group, and wherein R can be joined to the phenyl moiety to form a ring, R' is an aromatic- or heteroaromatic-containing group, each R.sub.a, independently of the others, is a halogen atom, an alkyl group, an alkoxy group, a nitrile group, a nitro group, an amide group, or a sulfonamide group, w is an integer of 0, 1, 2, 3, or 4, n is an integer representing the number of carbon atoms in each repeat alkylene oxide unit, and x is an integer representing the number of repeat alkylene oxide units, wherein said colorant has no more than one --OH, --SH, or primary or secondary amino group per molecule.