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Since its inception, Pyrex glass has become synonymous with heat-resistant glass, playing an incredibly important role in modern life. Pyrex glass was first developed in 1915 by Corning Incorporated in the United States, originating from laboratory glassware used in high-temperature and high-pressure environments. The invention of Pyrex aimed to address the issue of glassware breaking easily due to thermal shock in laboratories. By introducing borosilicate materials into the glass, Corning was able to give Pyrex glass exceptional heat resistance and thermal shock resistance, allowing it to remain stable under dramatic temperature changes without breaking easily. The name "Pyrex" comes from its heat-resistant and shock-resistant properties, and it is widely used in both scientific research and daily life.
As technology advanced, Pyrex glass gradually moved from laboratories to homes, particularly in the field of cookware. Many common heat-resistant glass products in the kitchen, such as baking dishes, measuring cups, and storage containers, are made of Pyrex. These products can withstand high-temperature cooking, are durable, and easy to clean, making them essential in many household kitchens. Additionally, Pyrex glass performs exceptionally well in scratch resistance, maintaining good transparency and integrity even after long-term use.
Properties of Pyrex Glass
Pyrex glass is renowned for its outstanding heat resistance and thermal shock resistance, making it widely trusted for everyday and scientific applications. These properties stem from its unique borosilicate composition, giving Pyrex superior physical and chemical stability compared to traditional glass.
High Heat Resistance
One of the most prominent features of Pyrex glass is its high heat resistance. Compared to ordinary glass, Pyrex can withstand extremely high temperatures without significant deformation or breaking. Its heat tolerance usually ranges from 300°C (and up to 500°C for certain specifications), making it the ideal material for cookware, laboratory equipment, and other high-temperature applications. For home cooking, this characteristic is especially useful, as Pyrex glass can safely handle high temperatures whether baking food or heating liquids.
This high heat resistance is due to the borosilicate structure of Pyrex glass, which has a much lower thermal expansion coefficient than regular soda-lime glass. Therefore, during heating and cooling, Pyrex does not generate significant internal stress, maintaining stability and resisting breakage. Moreover, Pyrex glass can endure high-temperature environments in microwaves and dishwashers, further enhancing its convenience and durability.
Thermal Shock Resistance
Another notable feature of Pyrex glass is its excellent thermal shock resistance, which allows it to remain structurally intact during sudden temperature changes. Thermal shock is a common issue for glass materials, where rapid heating or cooling causes uneven expansion or contraction, leading to concentrated stress and breakage. However, due to Pyrex’s low thermal expansion coefficient, it can withstand transitions from freezing to high-temperature environments or being rinsed with cold water immediately after being heated, without breaking.
This thermal shock resistance makes Pyrex highly practical for both home cooking and laboratory use. For example, when transferring a Pyrex baking dish from the refrigerator directly into a preheated oven, the glass remains stable and does not shatter due to rapid temperature changes. In laboratories, Pyrex glass can handle the intense temperature shifts required for various chemical reactions, making it the ideal material for experimental glassware.
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Chemical Composition of Pyrex
The chemical composition of Pyrex glass is approximately: SiO2 81%, Na2O 4.0%, K2O 0.5%, B2O3 13.0%, Al2O3 2.0%.
| Operating temperature range | -192°C to 500°C |
|---|---|
| Main component | Borosilicate Glass |
| Thermal expansion coefficient (10^-6 /°C) | 3.3 |
| Melting point (°C) | 約 820°C |
| Density (g/cm³) | 2.23 |
| Refractive index | 1.474 |
| Impact resistance | Excellent, especially against thermal shock. |
Avoid Direct Heating with Pyrex Glass
Although Pyrex glass is known for its heat resistance and shock resistance, it is not suitable for direct exposure to flames or the heating surfaces of stovetops. Localized heating can cause uneven thermal distribution, resulting in concentrated stress that may lead to breakage. Pyrex glass is designed for use with indirect heat sources, such as ovens or microwaves, rather than direct flames or stovetop heating.
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Conclusion
With its exceptional heat resistance and shock resistance, Pyrex glass holds an important place in both everyday life and professional fields. From kitchen cookware to scientific glassware, Pyrex is widely used due to its outstanding material properties. Its high heat tolerance ensures stability in high-temperature environments, while its excellent thermal shock resistance guarantees safe usage even in extreme temperature fluctuations.
The applications of Pyrex glass are not limited to kitchens and laboratories; it also plays a key role in many specialized fields, such as research and industrial equipment. Thanks to these characteristics, Pyrex glass has become the preferred material for environments that require enduring high temperatures or rapid temperature changes.
