what are the windows on the iss made of

The windows on the International Space Station (ISS) are made of a special material called fused silica or fused quartz. Fused silica is a type of glass that is highly transparent and resistant to extreme temperatures, radiation, and impacts from micrometeoroids and orbital debris. These windows are designed to provide astronauts with a clear view of space while ensuring the structural integrity and safety of the ISS.