What is Tempered Glass
What is Tempered Glass

Tempered glass, also known as toughened glass, is a type of safety glass that undergoes controlled thermal or chemical treatments to significantly increase its strength compared to normal glass. The tempering process involves heating the glass to over 1000 degrees Fahrenheit and then rapidly cooling it. This results in the outer surfaces of the glass cooling faster than the interior, creating a compressive stress layer on the surface. This layer significantly enhances the glass’s strength, making it about four times stronger than annealed (non-tempered) glass​​.

Key Characteristics and Applications of Tempered Glass

  • Increased Strength: The rapid contraction of the outer layer during manufacturing induces compressive stresses on the surface, balanced by tensile stresses in the body of the glass. This makes tempered glass significantly more robust and resistant to impact.
  • Safety Features: When broken, tempered glass shatters into small granular chunks instead of jagged shards, reducing the risk of injury. This characteristic makes it an ideal choice for safety applications.
  • Usage in Various Fields: Tempered glass is widely used in passenger vehicle windows (excluding windshields), shower doors, aquariums, architectural glass doors and tables, refrigerator trays, mobile phone screen protectors, bulletproof glass components, diving masks, and cookware.
  • Restrictions on Modification: Once tempered, the glass cannot be cut or ground; any such attempt will cause it to fracture.
  • Diverse Applications: Beyond the more common uses, tempered glass is also found in balcony doors, athletic facilities, swimming pools, building façades, exhibition areas, computer cases, and more.


Tempered glass’s combination of strength, thermal resistance, and safety features make it a versatile and widely used material in various applications, from vehicle windows to mobile phone screen protectors. Its unique manufacturing process and resultant properties distinguish it from regular glass, offering enhanced safety and durability where it matters most​​.

Eric Chan

Hi! I’m Eric and I work on the knowledge base at GadgetMates.com.  You can see some of my writings about technology, cellphone repair, and computer repair here.

When I’m not writing about tech I’m playing with my dog or hanging out with my girlfriend.

Shoot me a message at ericchan@gadgetmates.com if you want to see a topic discussed or have a correction on something I’ve written.

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