A light-activatable polymer composition and polymer composite includes a polymer binder selected from epoxy resins, silica filled epoxy, bismaleimide resins, bismaleimide triazines, fluoropolymers, polyesters, polyphenylene oxide/polyphenylene ether resins, polybutadiene/polyisoprene crosslinkable resins (and copolymers), liquid crystal polymers, polyamides, cyanate esters, or combinations thereof, the polymer binder being present in an amount from 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 96, or 97 weight-percent of the total weight of the polymer composition; a spinel crystal filler present in an amount from 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40, 45, 50, 55 and 60 weight-percent of the total weight of the polymer composition, and methods for making same are provided.