Polyether polyols based on bisphenol-S were prepared by alkoxylation and compared with analogs based on bisphenol-A, as well as standard aromatic polyester, and polyether polyols for viscosity and temperature stability. Thermooxidative stability was determined by thermo-gravimetric analysis, pyrolysis gas chromatography/mass spectroscopy, and evolved gas analysis mass spectroscopy. Incorporation of the sulfone moiety was found to dramatically improve the thermo-oxidative stability of the neat polyol. Significant char formation was observed with gas phase evolution of flame retardant SO2 and aromatic sulfone only apparent at about 600 degrees C. (C) 2016 Wiley Periodicals, Inc.