Class II ormosils in the systems: methyl, propyl, vinyl and phenyl silicates have been structurally investigated for their suitability as photonic materials and this paper is a precis of many data. From visible and near-infrared spectroscopy these ormosils have: (i) intrinsic optical windows in the visible and at 1.06, 1.3 and 1.55 μ m and (ii) low residual water, despite being synthesised at only 60° C. The residual water can be expelled under vacuum. Solid state29 Si nuclear magnetic resonance spectroscopy shows that matrix condensation increases as the organic content of the matrix is increased; this is accompanied by a decrease in BET surface area.