Various radiation-curable compositions for making optically clear high refractive index materials are provided. The radiation-curable compositions include: one or more aryl-containing compounds including one or more ethylenically unsaturated moieties: one or more reactive diluent compounds including an ethylenically unsaturated moiety; one or more heat-stabilizing compounds; and one or more photo initiators. Various methods of making optically clear high refractive index coatings are also provided.