Abstract: An improved process for coloring polymethacrylates or polyglutarimides in an extruder includes admixing the molten thermoplastic, conveyed directly from the polymerization operation, in an extruder mixing zone with a dispersion of at least one pigment, dye, or colorant in a suitable clear carrier, then conveying the admixed colored thermoplastic into an extrusion zone or injection molding zone.

Abstract: Decreasing the transmittal of near infra-red radiation through transparent glassy polymers, such as methacrylic ester polymers or those containing a high proportion of N-methyl dimethylglutarimide units, by use of a blended absorber is extremely difficult to accomplish because of the thermal instability of such absorbers under conditions necessary to process the glassy polymer. Use of very low levels of a specific class of thermally stable additives produces a thermally stable polymer blend which may be converted into transparent sheet exhibiting lowered transmittal of near infra-red radiation and useful for many glazing applications.