The proportional relationship between the infrared (IR) transmittance of a transparent material and its IR-induced heat transfer can be explained via a simple model. An agreement between the theory and the experimental work was examined by measuring the temperature rising inside a heat-insulated box with glass windows under IR irradiation, where the material of the glass windows was modified from corning glass (CG) to 9 at% Nb-doped TiO2 (TNO) fabricated by sputtering deposition. |