Articles of porous glass and process for preparing the same

A process for preparing an article of porous glass, the process comprising the steps of heat-treating a shaped body of base glass consisting essentially of about 48 to about 52% by weight of SiO.sub.2, about 8 to about 12% by weight of Al.sub.2 O.sub.3, about 14 to about 18% by weight of B.sub.2 O.sub.3, about 5 to about 7% by weight of Na.sub.2 O and about 15 to about 18% by weight of CaO at a constant temperature of about 680.degree. to about 800.degree. C. for about 2 to about 72 hours, and dissolving out the acid-soluble component with an inorganic acid.

A process for preparing an article of porous glass, the process comprising the steps of heat-treating a shaped body of base glass consisting essentially of about 48 to about 52% by weight of SiO.sub.2, about 8 to about 12% by weight of Al.sub.2 O.sub.3, about 14 to about 18% by weight of B.sub.2 O.sub.3, about 5 to about 7% by weight of Na.sub.2 O, about 7 to about 14% by weight of CaO and about 3 to about 10% by weight of MgO at a constant temperature of about 680.degree. to about 800.degree. C. for about 2 to about 72 hours, and dissolving out the acid-soluble component with an inorganic acid.