Poly(arylene ether)s with aromatic azo-coupled cobalt phthalocyanines in the side chain: synthesis, characterization and nonlinear optical and optical limiting properties

A novel poly(arylene ether) with azo-coupled cobalt phthalocyanine in the side chain (PAE-azo-CoPc) was prepared by 1,2-benzodinitrile, anhydrous cobaltous chloride and a novel azobenzene-containing poly(aryl ether) (PAE-azo-DCN) via a nucleophilic substitution polycondensation based on a novel bisfluoro monomer, 4-[(3,4-cyanophenyl)diazenyl]phenyl-2,6-difluorobenzoate. The obtained polymers were characterized and evaluated by FT-IR, 1H NMR, DSC and TGA. PAE-azo-CoPc exhibited higher glass transition temperature and better thermal stability than PAE-azo-DCN because of the introduction of cobalt phthalocyanine groups. The results of Z-scan measurements demonstrated that PAE-azo-CoPc showed reversible saturable absorption and positive refraction, and PAE-azo-DCN showed saturable absorption and negative refraction. By calculation, PAE-azo-CoPc exhibited larger third-order nonlinear optical susceptibilities than that of PAE-azo-DCN. The results of optical limiting measurements demonstrated that the PAE-azo-CoPc exhibited an excellent optical limiting response.