The method includes the following steps: (1) a microsheet of glass is drawn from a glass melt; (2) a reflective layer, such as silver, is deposited on one surface of the microsheet; (3) a first flexible backing layer, such as fiberglass, is bonded to the reflective layer; (4) the combination of the microsheet with the reflective layer and the first backing layer is formed over a mandrel which is preferably in the form of a parabolic cylinder; and (5) a honeycombed layer, with a second fiberglass backing layer, is then bonded to the first backing layer. The product produced by the steps 1-5 is then cured so that it retains the desired configuration; i.e. parabolic-cylindrical, after it is removed from the mandrel.