Poly(organophosphazenes) containing azo dyes

Abstract In this paper we describe a method for the functionalization of catenapoly[bis(4‐hydroxyphenoxy)‐λ5‐phosphazene] with diazonium salts to form new, deeply‐coloured, phosphazene copolymers containing variable amounts of azo dyes attached to the polyphosphazene skeleton. The degree of functionalization in these substrates is regulated in order not to exceed 20% of the sites available in the pristine polyphosphazene and to maintain a high percentage of unreacted, free, hydroxy groups, in the final, coloured copolymers. These species are still very reactive and able to undergo further functionalization reactions.