In an embodiment, a method for making an infrared radiation absorbing coating mixture comprises: forming an ITO coating mixture comprising ITO and a first coating matrix, wherein the first coating matrix comprises the partial condensate of a silanol, wherein the ITO coating mixture is free of colloidal silica; forming a colloidal silica coating mixture comprising colloidal silica and a second coating matrix, wherein the second coating matrix comprises the partial condensate of a silanol; and mixing the ITO coating mixture with the colloidal silica coating mixture to form a combined mixture. The combined mixture does not comprise a precipitate visible to the unaided eye after 2 weeks without stirring.