Q: Lots of lab glassware states the type of glass it is made of – Pyrex, Borosilicate Glass or Soda Lime.
What is the difference between these types of glass?
A: Different types of glass have different chemical compositions, meaning Borosilicate glass and Pyrex are better suited to heating.
Borosilicate glass has a higher porportion of silicone dioxide than Soda Lime glass, as shown on the table below;
| Compound | Borosilicate Glass – % content | Soda Lime Glass – % content |
| Silicon Dioxide SiO2 | 80.6 | 69 |
| Boron Trioxide B2O3 | 13 | 1 |
| Sodium Oxide Na2O | 4 | 13 |
| Aluminium Oxide Al2O3 | 2.4 | 4 |
This difference means that Borosilicate glass does not expand as much on heating, so it is less likely to break when heated.
Pyrex is one particular blend of Borosilicate glass, with a particularly high heating tolerance.
Soda Lime glass is sometimes used for glassware which is not likely to be directly and strongly heated, for example petri dishes or TLC chromatography tanks.
Borosilicate glass or Pyrex is usually used for glassware that may be directly heated, such as beakers or boiling flasks.
if you would like to know about the right type of glassware to use we have Product Guides to help you decide.
To find out more, follow the links above or contact us if you need any help in choosing lab glassware;