R. sup. 5 is a divalent hydrocarbon radical; or a carbon atom which is part of a cyclic group in the radical G; or a radical of formula ##STR3## where R. sup. 7 is a divalent hydrocarbon radical; if n=1, G is a monovalent organic or inorganic radical, free of phenolic hydroxyl groups or other groups which substantially interfere with radical polymerization, containing one free-radically copolymeri