An H2O2-assisted, sol-gel synthesis route to precursors to magnesium silicate thin films is described. Films having ratios of Mg to Si from 1 to 3 were prepared by spin-coating. On substrates such as silicon, aluminum, steel, glass, and fused silica, repeated coatings were applied, without intermittent treatment, to give ∼0.5 μm thick films. Crack-free consolidation was achieved by conventional or microwave heating. Densification of the films on silicon was studied by IR spectroscopy, ellipsometry, and microhardness measurements; IR analysis indicated that these films were amorphous to at least 750°C. At high enough temperatures, durable films were obtained that exhibited antireflective properties.