Chemically Strengthened Glass
Chemically strengthened glass is a type of glass that has increased strength. When broken it still shatters in long pointed splinters similar to float (annealed) glass. For this reason, it is not considered a safety glass and must be laminated if a safety glass is required. Chemically strengthened glass is typically six to eight times the strength of annealed glass.
The glass is chemically strengthened by submerging the glass in a bath containing a potassium salt (typically potassium nitrate) at 450 °C (842 °F). This causes sodium ions in the glass surface to be replaced by potassium ions from the bath solution.
Unlike toughened glass, chemically strengthened glass may be cut after strengthening, but loses its added strength within the region of approximately 20 mm of the cut. Similarly, when the surface of chemically strengthened glass is deeply scratched, this area loses its additional strength.
Chemically strengthened glass was used on some fighter aircraft canopies.
Read more about this topic: Architectural Glass
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