Borosilicate glass
Borosilicate glass is a special type of glass known for its unique properties, making it ideal for a variety of applications. Here are its key characteristics:
- High Thermal Resistance: One of the most notable properties of borosilicate glass is its ability to withstand extreme temperature changes without breaking or cracking. This makes it highly resistant to thermal shock, which is why it's often used in laboratory glassware, and some industrial equipment.
- Chemical Resistance: Borosilicate glass has excellent resistance to many chemicals, making it ideal for use in labs and chemical processing environments. It does not easily react with acids, bases, or other corrosive substances.
- Durability: This type of glass is known for being durable and hard, yet it's also relatively lightweight. While it's stronger than ordinary glass, it can still break if dropped on a hard surface, but its resistance to cracking is far superior.
- Clarity: Borosilicate glass is optically clear, which makes it useful for applications requiring transparency, like high-quality glassware, medical instruments, and optics.
- Low Expansion: Borosilicate glass has a low coefficient of thermal expansion, meaning it doesn't expand or contract as much with temperature changes compared to other types of glass. This property contributes to its ability to withstand thermal shock.
- Non-reactive Surface: The non-reactive surface of borosilicate glass means it won't leach chemicals into food, liquids, or materials in contact with it, which is crucial for food-safe applications or experiments requiring purity.
Because of these characteristics, borosilicate glass is commonly used in laboratories, cooking, pharmaceuticals, and even in the production of high-performance optics and electronics.
Here's a overview of common technical data for borosilicate glass, (click/load more) particularly types like Borosilicate 3.3 (e.g., SCHOTT's DURAN, Corning Pyrex, etc.) which is widely used in scientific and industrial settings.
Chemical Composition (Typical)
Oxide
Approx. % by Weight
SiO₂ (Silicon Dioxide)
80.5% – 81%
B₂O₃ (Boron Trioxide)
12.5% – 13.5%
Na₂O (Sodium Oxide)
~4%
Al₂O₃ (Aluminum Oxide)
~2.5%
Thermal Properties
Property
Value
Softening Point
~821 °C
Annealing Point
~560 °C
Strain Point
~525 °C
Max Working Temp (cont.)
~500 °C
Thermal Expansion (20–300 °C)
~3.3 × 10⁻⁶ /K
Thermal Shock Resistance
Excellent (ΔT ~165 °C or more)
Mechanical Properties
Property
Value
Density
~2.23 g/cm³
Young's Modulus
~63 GPa
Poisson's Ratio
~0.2
Compressive Strength
~1000 MPa
Bending Strength
~40–100 MPa (depends on finish)
Hardness (Mohs)
~6.5
Electrical Properties
Property
Value
Electrical Resistivity
~10¹⁰ to 10¹⁴ Ω·cm
Dielectric Constant (1 MHz)
~4.6
Dielectric Strength
~40–50 kV/mm
Optical Properties
Property
Value
Transmission Range
~300 nm – 2500 nm
Refractive Index (n₅₈₉)
~1.47
UV Transmission
Moderate (limited below 320 nm)
This makes borosilicate glass ideal for:
- Lab equipment
- Lighting components
- Chemical processing
- Optical components (non-UV applications)
