The process of forming a porous glass structure through an ion exchange between the alkali cations in the glass and salt melt’s cations with a smaller ionic radius has been investigated. Using methods of optical, electronic, atomic force microscopy, and X-ray 3D tomography the effect of the composition of the glass and the salt melt, the temperature, and the reaction time on the structure of the resulting porous material, the total and open porosity of the glass have been determined.