Transparent and almost colourless, with near-zero thermal expansion and excellent resistance to temperature differences and thermal shock, for flame viewing panels in wood, pellet and gas fireplaces and stoves.
ROBAX® is a transparent glass-ceramic developed by SCHOTT for fireplace and stove flame viewing panels; material, edges, hole positions, sealing and mounting structure must all be assessed together.
Average coefficient of linear thermal expansion from 20–700 °C is (0 ± 0.5) × 10⁻⁶/K.
The official documentation states that under the specified test conditions it does not break from thermal stress or cold-water thermal shock up to 700 °C.
Standard ROBAX® is transparent and almost colourless, and is available in flat, curved and bent forms.
SCHOTT ROBAX® is a transparent glass-ceramic meeting the requirements of EN 1748 Part 2. The official documentation summarises its core characteristics as transparency, near-zero thermal expansion, high-temperature stability and good mechanical and chemical durability.
ROBAX® is still a brittle material, and its strength is affected by surface defects, edge processing, drilled holes, dimensions, thickness, load duration, environment and mounting method. The design should avoid local clamping, hard contact and the transfer of frame distortion, and should use heat-resistant, permanently elastic sealing and spacing materials.
| Material and standard | Transparent glass-ceramic; chemical composition meets the requirements of EN 1748 Part 2 |
|---|---|
| Density | Approximately 2.6 g/cm³ (25 °C) |
| Bending strength | Approximately 35 MPa (DIN EN 1288 Part 5, normal-use surface condition) |
| Coefficient of thermal expansion (CTE) | （0 ± 0.5）× 10⁻⁶/K（20–700°C） |
| Resistance to temperature difference, RTD | Under specified conditions Tmax ≤ 700 °C without thermal stress fracture |
| Thermal shock resistance, RTS | Under specified conditions for 15 °C cold-water shock, Tmax ≤ 700 °C without thermal stress fracture |
| Temperature / time load | 610 °C / 1,000 h; the current official page also lists a short-term maximum of 760 °C (non-uniform heating conditions) |
| Water resistance class | HGB 1（ISO 719） |
| Acid resistance class | At least S2 (DIN 12116) |
| Alkali resistance class | At least A1 (referencing ISO 695) |
| Appearance | Transparent with very little body colour; both faces smooth with a high-quality silky matte appearance |
The large-format transparent flat sheet listed in the official SCHOTT brochure is 1,954 × 1,100 mm; standard flat panel thicknesses are 4.0 and 5.0 mm.
Edge length ≤500 mm: ±1.0 mm; edge length >500 mm: ±1.5 mm
Sheet ≤0.3% × measured length; cut-size panels ≤0.3% × diagonal
Available on request; the official brochure lists hole diameters from 7 mm, with positions limited by thickness and geometry
Curved and bent forms are usually offered in 3, 4 and 5 mm; the exact geometry must be confirmed per project
Other thicknesses, curvatures, bend angles, decoration and special profiles are confirmed against the SCHOTT product range, sheet and project conditions; this page does not guarantee stock.
The official SCHOTT brochure gives typical transmission curves for transparent ROBAX® in 4 mm and 5 mm over roughly 0–4,000 nm, based on a single measurement.
View the SCHOTT official transmission spectrum PDF ↓
Processing focuses on protecting the glass-ceramic surface and edges, and on bringing hole positions, sealing, clamping and frame thermal deformation into a single design.
Precision glass processing services. Precision glass grinding. For borosilicate glass, aluminosilicate glass, …
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We plan the glass cutting route around dimensions, datums, edge condition and downstream operations, reviewing outline, cutting allowance and delivery requirements against the drawing.
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Grinding and polishing operations are arranged around thickness, parallelism, flatness and surface requirements, with the process route and inspection method confirmed per project.
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We control particles, residues and water marks after processing, and confirm cleaning, handling and packaging requirements against coating, bonding or assembly needs.
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Glass dimensions, edges and surfaces are inspected against the drawing and the agreed acceptance items, with inspection methods, sampling scope and delivery records defined.
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We address sharp edges and local edge defects after cutting, confirming edge grinding and chamfer styles and edge acceptance criteria against assembly requirements.
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For micro-holes, hole arrays and local openings in glass, we evaluate laser drilling options based on material, thickness and hole geometry.
View ProcessingThe specific product variant, dimensions, decoration, thermal performance and mounting requirements must be validated against SCHOTT documentation and the complete appliance design.
No. ROBAX® is a transparent glass-ceramic developed by SCHOTT, characterised by near-zero thermal expansion, high-temperature stability and thermal shock resistance.
Not in that sense. The current SCHOTT page gives a short-term maximum of 760 °C, while the official brochure lists 610 °C / 1,000 h; in practice the temperature difference, duration, dimensions and mounting structure must all be taken into account.
We can evaluate this. The official brochure lists hole diameters from 7 mm, but hole positions are limited by thickness, dimensions, hole diameter, corners and panel geometry.
No, it is not a fixed guaranteed value for finished parts. The official documentation states that strength is affected by surface, edges, holes, load, environment, dimensions, thickness and mounting method.
Please provide flat or three-dimensional geometry, dimensions, thickness, hole positions, edges, decoration, operating temperature, mounting structure, quantity and acceptance conditions.
Send the drawing, quantity, temperature conditions and mounting structure, and we will confirm the original material, processing, inspection and packaging requirements as one set.