Poly(arylene sulfone)s containing 9,9′-spirobifluorene: synthesis and excellent optical properties

Poly(arylene sulfone)s (PASs) containing a 9,9′-spirobifluorene (SBF) skeleton in the main chain were synthesized in high yields by the oxidation of the corresponding poly(arylene thioether)s. The PASs exhibited good thermal stability ( T g 257–370 °C, T d5 >400 °C under nitrogen) and showed high solubility in ordinary organic solvents, such as CHCl 3 , N -methylpyrrolidone (NMP) and N , N -dimethyl formamide (DMF). All films of PASs showed higher refractive indices in the range of 1.65–1.67 at 587.6 nm than those of commercially available polysulfone, whereas they hardly showed birefringence. These excellent optical and thermal properties are derived from the C 2 symmetry and high aromatic component of the SBF moiety.