Improved electro-optic devices are provided which may be in the configuration of variable transmittance windows, variable transmittance eyeglasses, variable transmittance light filters and displays and other devices wherein the transmittance of light therethrough automatically varies as a function of light impinging thereon. The electro-optic devices include a self-erasing electro-optic medium, and the transmittance of light through such medium varies as a function of electrical signals applied thereto through the agency of at least one photovoltaic cell, enclosed within the electro-optic device, and obviating the necessity of providing external drive voltage or external bleeder resistors or external wiring. In addition, a method and apparatus are provided for making such electro-optic devices.