Window in thin polishing pad

A method of making a polishing pad, comprising:

• forming an aperture through a polishing layer stack from a polishing surface to a bottom surface of the polishing layer to expose a first adhesive layer that is positioned on and contacts the bottom surface of the polishing layer stack and spans the aperture and the polishing pad, the polishing layer stack including a polishing layer having the polishing surface, wherein the first adhesive layer secures the bottom surface of the polishing layer stack to a fluid-impermeable layer that layer spans the aperture and the polishing pad;
• positioning a pre-formed light-transmitting body in the aperture in the polishing layer stack such that a lower surface of the light-transmitting body contacts and adheres to the first adhesive layer;
• dispensing an adhesive sealant into a gap that separates the light-transmitting body from side-walls of the aperture to laterally fill the gap;
• and
• curing the adhesive sealant.