The invention relates to a polymerization and post-tempering device (10) for tempering, in particular post-tempering, dental restoration parts (54) made of polymerizable plastics. At least one light source (38) which emits light in the visible and/or ultraviolet wavelength range and a light chamber with a door (14) to the light chamber are provided. The door (14) comprises a window (20) with a window pane (22) which consists of at least two layers (56, 58) whose layer facing the light chamber reflects at least 90%, in particular approximately 95%, of light, and whose layer facing away from the light chamber filters out UV light and/or blue light.
