A moisture-adsorbing material incorporated into an IGU spacer or edge system to help keep the sealed cavity below the moisture level that produces visible condensation.
Jeran Renz · Image source · CC BY-SA 4.0 · Image source · License
Meaning and boundaries
Desiccant cannot compensate indefinitely for leakage, saturated materials, fabrication defects, or a damaged edge seal.
Why it matters in glass restoration
The concept explains why internal fogging is an assembly issue that surface polishing cannot solve.