The invention relates to a polymer composition, comprising: (i) at least one thermoplastic resin having a glass transition temperature of at least about 220° C.; (ii) at least one phenylalkoxysilane, biphenol, trisilanolphenyl polyhedral oligomeric silesquioxane, or mixture of two or more thereof; (iii) inorganic particulates having an average particle size in the range up to about 100 nanometers dispersed in the thermoplastic resin, the inorganic particulates having an index of refraction in the range from about 1.4 to about 3; and (iv) an effective amount of at least one dispersant to disperse the inorganic particulates in the thermoplastic resin; with the proviso that when the trisilanolphenyl polyhedral oligomeric silesquioxane is in the form of particulates with an average particle size up to about 100 nanometers, the trisilanolphenyl polyhedral oligomeric silesquioxane particulates are optionally used as both component (ii) and as a partial or complete replacement for the inorganic particulates in component (iii). The polymer composition may be a high temperature thermoplastic suitable for forming, such as by molding, optical articles such as lenses.