A method of using nanoscopic silicon containing agents for in situ formation of nanoscopic glass layers on material surfaces is described. Because of their tailorable compatibility with polymers, metals, composites, ceramics, glasses and biological materials, nanoscopic silicon containing agents can be readily and selectively incorporated into materials at the nanometer level by direct mixing processes. Improved properties include gas and liquid barrier; stain resistance; resistance to environmental degradation: adhesion; printability; time dependent mechanical and thermal properties such as heat distortion, creep, compression set, shrinkage, and modulus; hardness and abrasion resistance; oxidation resistance; electrical and thermal conductivity; and fire resistance.