An apparatus for protecting an optical device from contamination is disclosed. The apparatus includes a window disposed between the optical device and a contaminating environment, the window being rotatable about a rotational axis and including an outwardly facing surface that is curved in at least one direction about the rotational axis. The apparatus also includes a bezel enclosing a portion of the outwardly facing surface and defining a clear aperture for transmission of electromagnetic radiation to or from the optical device. The bezel includes a seal extending around a periphery of the clear aperture and is configured to cause the seal to conform to the outwardly facing surface when the window and bezel are urged into contact with each other. The apparatus also includes an actuator operable to cause relative rotation between the window and the bezel to cause the outwardly facing surface to move with respect to the bezel. The apparatus further includes a seal configured to dispense a film onto a portion of the outwardly facing surface that enters the clear aperture during the relative rotation, the film being operable to reduce bonding of optical contaminants to the outwardly facing surface within the clear aperture while transmitting the electromagnetic radiation to or from the optical device through the clear aperture. The seal is configured to dislodge contaminants entrained in the film or adhered to a portion of the outwardly facing surface moving out of the clear aperture during the relative rotation.