The invention is directed to chemical-mechanical polishing pads comprising a transparent window. In one embodiment, the transparent window comprises an inorganic material and an organic material, wherein the inorganic material comprises about 20 wt. % or more of the transparent window. In another embodiment, the transparent window comprises an inorganic material and an organic material, wherein the inorganic material is dispersed throughout the organic material and has a dimension of about 5 to 1000 nm, and wherein the transparent window has a total light transmittance of about 30% or more at at least one wavelength in the range of about 200 to 10,000 nm. In yet another embodiment, the transparent window comprises an inorganic/organic hybrid sol-gel material. In an additional embodiment, the transparent window comprises a polymer resin and a clarifying material, wherein the transparent window has a total light transmittance that is substantially higher than a window comprising only the polymeric resin.