Ceramic Fireplace Glass Cut to Size | 700°C Stove Glass

SCHOTT ROBAX® is a lithium aluminosilicate glass-ceramic with a thermal expansion coefficient of essentially zero — 0 ± 0.3 × 10^-6/K across 20–700°C. That single number is why it survives in a firebox. A panel can sit at 700°C in the center while the frame edge stays near room temperature, and the material does not move enough to build stress. Tempered soda-lime glass fails at roughly a third of that differential.

It also passes heat rather than trapping it. ROBAX® transmits strongly in the shortwave infrared band — the part of the spectrum you actually feel as warmth — so a closed firebox still radiates into the room instead of venting its output up the flue.

Used in wood stove and fireplace viewing windows, pellet stove doors, boiler sight ports, pizza oven and commercial broiler windows, and industrial furnace inspection glass. Compared to borosilicate 3.3, which tops out near 450°C, ROBAX® runs continuously at 700°C and peaks at 760°C. Compared to tempered soda-lime, it will not shatter on thermal shock — but note that it is not tempered and cannot be. It breaks into shards, not dice, and does not qualify as impact safety glazing.

Supplied cut to your dimensions from full ROBAX® sheet in 3mm, 4mm and 5mm (0.118", 0.157", 0.197"). Dimensional tolerance ±0.5mm. Edges seamed as standard; ground, polished, radius corners, notches and holes available. Send a drawing or a template of your old panel.