▎ 摘　　要

NOVELTY - Optical endpoint detection window, comprises 50-70 pts. wt., preferably 55-65 pts. wt. isocyanate-terminated pre-polymer, 30-50 pts. wt., preferably 35-45 pts. wt. curing agent, and 0.1-10 pts. wt., preferably 0.5-5 pts. wt. surface modified nano-material, where the sum of isocyanate-terminated pre-polymer and curing agent is 100 pts. wt.. USE - The window is useful for chemical mechanical polishing pads. ADVANTAGE - The window resists photo-degradation and hydrolysis while still has high light transmittance. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing optical endpoint detection window, comprising stirring and mixing the surface modified nano-material and curing agent at 50-70degrees Celsius for 2-3 hours, adding to isocyanate-terminated pre-polymer, stirring and de-foaming, injecting obtained combined liquid into mold, heating the mold to 80-130degrees Celsius for 12-18 hours, cooling to 20-30degrees Celsius for 1-3 hours, and de-molding.