Planar optical waveguides of some novel phosphazene inorganic polymers with high glass transition temperatures, T-g greater than or equal to 150 degrees C, have been prepared by spin-coating on glass and quartz substrates. Thicknesses between 0.5 and 2 mu m and index steps of about Delta n similar to 0.2 (for quartz) and Delta n similar to 0.1 (for glass) at lambda = 0.633 mu m have been achieved. From one to five modes have been observed at wavelengths ranging from the green to the near infrared. Refractive indices have been well fitted to a Sellmeier dispersion equation. Waveguide losses are estimated to be around 10 dB/cm.