Patent ID: 6998102

Claim:
A process for producing transparent, monolithic porous glass, comprising: providing a preformed gel containing a solvent and which shrinks during drying due to strong capillary forces at the liquid-solid-vapor interface, placing the gel in a mold, placing the mold in a vessel capable of containing pressures up to 50 psi at a temperature up to 300°, positioning in the vessel a quantity of the same solvent as in the gel, loosely sealing the mold in the vessel whereby there is leakage from the vessel above a selected pressure, increasing the temperature of the vessel from room temperature to a first temperature in a first time period, to increase pressure in the vessel to about 50 psi, allowing the pressure in the vessel to leak out over a second time period to a pressure of about 15 psi, increasing the temperature in the vessel to a second temperature in a third time period, while releasing any pressure increase above 15 psi, allowing the vessel to cool and evacuating the vessel while cooling, removing the mold from the vessel, and removing a transparent porous glass monolith from the mold.