Abstract: A compound for forming bodies for generating heat from radiant luminous energy consists of a fluid mixture of 30 to 50% by weight of a reticulatable resin and 70 to 50% by weight of an intimately mixed and finely divided charge, 30 to 60% of which by weight consists of an absorbent black charge and 70 to 40% of which by weight consists of a diffusing white charge. The compound may contain up to 25% glass fibers, expressed as a percentage of the weight of the resin. The black charge may include one or more of the following: graphite and the oxides of iron, copper, manganese, nickel and cobalt. The white charge may contain one or more of the following: alkaline earth carbonates and sulphates and the oxides of silicon, beryllium, magnesium, aluminium, zirconium and thorium. The compound is prepared by homogenously mixing the ingredients in a mixing mill at ambient temperature. The heat generating bodies are formed by casting and polymerizing the compound.