There is often a common misconception regarding the safety of drinking water from high borosilicate glass cups. This misunderstanding arises from a lack of understanding about borosilicate glass. High borosilicate glass, also known as hard laminated glass, is a unique type of glass that is produced by utilizing the electrical conductivity characteristics of laminated glass at high temperatures. It possesses several beneficial properties such as low moisture content, heat resistance, high toughness, high light transmittance, and high organic chemical reliability. It is commonly used in the production of turntables, high-temperature tea cups, and various glass water cups available in the market.
So, why are high borosilicate glass cups considered safer? The main reason is that high borosilicate glass has an exceptionally low coefficient of linear expansion, which is approximately one third of that of ordinary glass. This characteristic helps to reduce the damage caused by temperature gradient stress, making it more resistant to fractures. Additionally, high borosilicate glass exhibits minimal shape errors, making it a preferred material for applications such as telescopes and reflective lenses. While it is highly resistant to thermal shock, it is important to note that rapid temperature changes can still cause cracks in high borosilicate glass. However, unlike regular glass that shatters, cracks in high borosilicate glass tend to form blocks, which can mitigate the extent of damage.
In daily life, how can one distinguish whether a glass is made of high borosilicate material? One way is to recall the chemistry experiments conducted in middle school, particularly the use of test tubes. Those test tubes were made of high borosilicate glass due to its high organic chemical reliability and immediate heat resistance. Typically, borosilicate glass cups have clear definitions, lightweight designs, and relatively thinner bottoms. On the other hand, cups with thicker bottoms are less likely to be made of borosilicate glass. Moreover, the double-layered glass cups often seen in the market are usually made of high borosilicate Pyrex glass. High borosilicate glass offers higher temperature resistance, albeit at a higher cost, and provides greater clarity and smoother texture compared to ordinary glass. Even feeding bottles for babies are made of high borosilicate glass, highlighting its evident safety factor. Considering these factors, it becomes apparent that there is no cause for concern regarding the safety of drinking water from high borosilicate glass cups.