The corrosion protective effect of the surface modification of corrosion sensitive glass surfaces and of ORMOCER (organically modified ceramic) coatings is investigated. The surface modification provides a modest protection, perhaps useful for additional protection in combination with external glazing. The advantage is the invisibility of the modification due to the thickness of several molecular layers. An effective protection can be obtained by diffusion barrier pigmented ORMOCER coatings. First outdoor results on medieval glasses are hopeful, but long period experience is necessary for wider application.