Phase separated glasses

A method of making a glass article, comprising

• forming a molten glass, the molten glass undergoing spinodal decomposition to produce a phase separated molten glass comprising a first phase, a second phase, and a total SiO2 content in a range from about 59 mol % to about 69 mol % and a B2O3 content in a range from about 9 mol % to about 20 mol %;
• drawing the phase separated molten glass into a glass sheet;
• and
• exposing the glass sheet to a first acid solution at a temperature between about 60° C. to about 95° C. for about 16 hours to about 24 hours to remove at least a portion of the second phase from the glass sheet and obtain a porous glass sheet comprising a total silica content greater than about 95 mol %.