The foam board was prepared by putting the hydrated glass powders into a square stainless steel mold about 120 ± 1 mm on a side. After heating at 350 °C for 2 h, the foam was obtained. The appearance and cross section photo of the foam board are shown in Fig. 4. The bulk density of the foams was determined from the weight-to-volume ratio, using a caliper and a digital balance. The accuracy of the calculation was estimated to be ± 0.01 g/cm3. TC 3000 Thermal Conductivity Meters was used to investigate the thermal insulation ability of the foam board, with an accuracy of ± 1–2% in all range (0.001–20 W/(m·K)).