Polishing pad with endpoint window

A polishing pad for chemical mechanical polishing comprising a polishing layer having a top polishing surface, a bottom surface and a thickness, the polishing layer comprises a porous polishing material and a window region, wherein the window region comprises a transparent window that has an exposed top surface and an exposed bottom surface to enable light to transmit through the polishing pad in the window region, the exposed top surface of the transparent window is recessed from the top polishing surface, the transparent window extending from the recess region to the bottom surface of the polishing pad, the window region further comprises a peripheral portion of the polishing material in contact with side edges of the transparent window, the peripheral portion of polishing material has a top surface that is recessed from the top surface of the top polishing surface and wherein the transparent window is non-porous and wherein a portion of the top surface of the peripheral portion adjacent to the transparent window is coplanar with the top surface of the transparent window and wherein the exposed bottom surface of the transparent window is coplanar with the bottom surface of the polishing layer.