In daily life, borosilicate glass cups are commonly used for brewing tea and coffee due to their high transparency and good chemical stability. Their maximum withstand temperature is a core concern for users. The maximum instantaneous temperature a typical borosilicate glass cup can withstand is approximately 150℃, while the long-term safe usage temperature is below 120℃. This characteristic stems from its unique material composition and manufacturing process.
The temperature resistance of borosilicate glass is essentially determined by its chemical composition. It uses silicon dioxide as the main raw material, with 10%-15% boron anhydride added as a flux. Compared to ordinary soda-lime glass, the addition of boron restructures the glass's molecular structure, creating a more stable network architecture. This structure not only reduces the glass's coefficient of thermal expansion, significantly improving its thermal stability, but also enhances its high-temperature resistance, allowing it to maintain its shape stability over a wider temperature range and preventing breakage due to sudden temperature changes or prolonged exposure to high temperatures.
It is important to clarify that the 150℃ instantaneous maximum temperature is not an absolute threshold; actual temperature resistance is affected by various factors. Firstly, the manufacturing process matters. High-quality borosilicate glass undergoes high-temperature annealing, fully releasing internal stress and bringing its temperature resistance closer to the theoretical value. In contrast, poorly manufactured products may have hidden cracks, making them prone to breakage at high temperatures. Secondly, the rate of temperature change is crucial. While borosilicate glass has good thermal shock resistance, instantaneous exposure to temperatures above 150°C (such as pouring in boiling water) can still cause it to shatter due to excessive localized temperature differences, especially for thicker-walled models.
In daily use, proper methods are essential to mitigate risks. It is recommended to preheat the cup with a small amount of warm water before adding boiling water to avoid sudden temperature changes. Do not place an empty cup directly on an open flame or high-temperature heating device. Even heat-resistant cups can suffer from localized overheating and damage to the glass structure if left dry for extended periods. Furthermore, for borosilicate glass cups with handles, sealing rings, or other accessories, the materials of these accessories may not be heat-resistant. The overall usage temperature should be determined based on the tolerance of these accessories, generally not exceeding 100°C.
Compared to ordinary glass, high borosilicate glass has a significant advantage in high-temperature resistance. Ordinary soda-lime glass can only withstand temperatures up to around 80°C and has poor thermal shock resistance, while high borosilicate glass can withstand instantaneous temperatures of 150°C and has good thermal shock resistance, making it suitable for most everyday hot beverage scenarios. At the same time, its excellent chemical stability means it will not release harmful substances at high temperatures, ensuring greater safety, which is also an important reason for its widespread use in the food container industry.