Quartz Glass Sheet, Tempered Glass Sheet and High Borosilicate Glass Sheet

Industry Guide News — Glass sheets are widely selected for optical, lighting, industrial observation and protective components. Quartz glass, tempered glass and high borosilicate glass sheets are three common options, yet they differ fundamentally in composition, core performance and suitable working conditions. This guide helps engineers and buyers make correct material selection for their projects.

Quartz glass sheet is made of fused silica with SiO₂ purity above 99.99%. It is melted at ultra-high temperature and features an extremely low thermal expansion coefficient. It can operate continuously at 1100°C and withstand sharp hot-cold alternation without cracking. Its biggest highlight is excellent UVC transmittance at 254 nm, plus outstanding chemical inertness against most strong acids. It also delivers stable electrical insulation. The main limitation is relatively low mechanical impact strength and higher production cost.

Tempered (strengthened) glass sheet is soda-lime glass treated by thermal tempering. The strengthening process creates surface compressive stress, boosting its impact resistance 4–5 times higher than ordinary annealed glass. It breaks into small granular fragments for better safety. However, its heat resistance is limited; the long-term working temperature is generally below 250°C. It blocks UV light and has average acid resistance. Its core advantage lies in low cost and high mechanical safety.

High borosilicate 3.3 glass sheet contains roughly 78% silica and 13% boron trioxide. It balances moderate heat resistance and affordable pricing. Its continuous service temperature reaches around 450°C with decent thermal shock resistance. It works well for general chemical corrosion but cannot transmit UVC wavelengths effectively. It is far cheaper than quartz glass and easier for custom cutting and forming.

Application scenarios are clearly separated. Quartz sheets are preferred for UVC germicidal lamps, high-temperature furnace windows,

semiconductor fixtures, spectral detection and photochemical reactors. Tempered glass sheets are widely used for safety panels, equipment protective covers, observation windows and household appliance panels where mechanical impact protection is prioritized. High borosilicate sheets are the standard choice for laboratory vessels, general sight glasses, low-heat lighting covers and conventional chemical testing equipment.

For product designers, the selection rule is straightforward: pick quartz for UVC transmission and extreme high temperature; choose tempered glass when impact safety is the top requirement; adopt borosilicate for regular heat-resistant applications with budget control.