How is tempered glass produced?

Tempered glass is produced through a specific process that involves heating and then rapidly cooling the glass. This method gives the glass increased strength and safety characteristics compared to standard glass. In the correct process, the surface of the glass is heated to a temperature where it begins to soften, typically around 600 to 720 degrees Celsius. After this, it is cooled quickly through a process known as quenching, which hardens the outer layers of the glass while the interior remains softer.

This differential cooling causes the outer layers of the glass to contract while the interior remains expanded, resulting in compressive stresses on the surface. This is precisely what enhances its strength, resilience, and ability to withstand impact and thermal stress. If the glass does break, tempered glass shatters into small, blunt pieces instead of sharp shards, making it safer for use.

The other methods mentioned in the other options do not accurately describe how tempered glass is produced. For example, rapidly cooling glass after shaping refers more to the initial stages of glassmaking rather than the specific process that gives tempered glass its unique properties. Mixing polymers with glass pertains to composite materials, which is a different procedure entirely. Lastly, applying a coating involves adding a layer on top of the existing glass but does not