the present invention includes polymer films that comprise lanthanum hexaboride and an epoxy agent . the lanthanum hexaboride and epoxy agent can be incorporated into or onto a polymer film in any suitable manner . the addition of an epoxy agent surprisingly provides a stabilization effect to the lanthanum hexaboride , which allows for the production of polymer films that advantageously absorb infrared radiation and resist environmental degradation . polymer films thus produced have a significant number of applications , for example , but not limited to , display devices , protective coverings , and glazing film applications .