Aluminosilicate glass is approximately how many times stronger than borosilicate glass?

• A. 2x
• B. 3x
• C. 6x
• D. 10x

Answer: (C)

Strength comes from a compressive surface layer created during chemical tempering; this layer helps resist crack initiation and stops cracks from growing when the glass is stressed. Aluminosilicate glass is subjected to a more aggressive ion-exchange process than borosilicate, producing a deeper, higher compressive zone. That means it markedly improves bending strength and resistance to surface flaws compared with borosilicate. In typical comparisons, the gain from this stronger surface compression is large, so the option representing the strongest multiplier among the choices best matches how much stronger aluminosilicate glass can be in practice.