Waveguides having high stability are disclosed (and other devices and materials including but not limited to coatings, passivation materials, glob top materials, underfill materials, materials for IC and other applications, microlenses and any of a wide variety of optical devices) that benefit by being formed of a novel hybrid organic-inorganic material. In one embodiment of the invention, a method for making a waveguide includes: forming a lower cladding layer on a substrate; forming a core layer after the lower cladding layer; and forming an upper cladding layer after the core layer; wherein the lower cladding layer, core layer and/or upper cladding layer comprises a stable material with a relatively high glass transition temperature. Preferably the material is one that does not degrade or otherwise physically and/or chemically change upon further processing or when in use. Preferably the stable waveguide material of the invention can be heated in supercritical water vapor at 2 atm and at 120 C. for 2 hours without degradation (e.g. after which optical absorption, polarization dependent loss and/or refractive index change remains unchanged .+-.5%).