Disclosed is a compound of one of the formulae
##STR1##
##STR2##
wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7,
R.sub.8, R.sub.9, and R.sub.10 each, independently of the others, is an
alkyl group, an aryl group, an arylalkyl group, or an alkylaryl group,
R.sub.11 and R.sub.12 each, independently of the others, is an alkylene
group, an arylene group, an arylalkylene group, or an alkylarylene group,
G is a cationic moiety, A is an anionic moiety, n is an integer
representing the number of repeat --OSi(R.sub.7)(R.sub.8)-- monomer units,
a is an integer representing the number of repeat --OSi(R.sub.10)(R.sub.12
-lightfastness moiety)-- monomer units, and c is an integer representing
the number of repeat --OSi(R.sub.9)(R.sub.11 -hydrophilic moiety)--
monomer units.
