Optical windows for intracorporeal devices, intracorporeal devices comprising a window and a method for forming a window for an intracorporeal device are provided. The method comprises placing within a mold an assembly comprising a mandrel located within a pair of parts separated by a collar of window material, heating the window preform effective to cause the window material to soften, and applying force to urge together the pair of parts to deform the window material so as to form a window. The intracorporeal devices, such as imaging devices, include guidewires, catheters, endoscopes. In addition, the method is suitable for joining plastic parts to other parts, such as metal and ceramic parts.