Not all bent panes with a special geometry can be thermally toughened and so sunglass industry offers chemical strengthening for these panes. Chemical strengthening is primarily used to strengthen gravity bent glass with unconventional formats.

Strengthening gravity bent glass

In a separate part of the plant, the panes of glass are prepared for this treatment in a potassium salt bath.

While the panes are immersed in this salt bath, the strengthening takes place place via the exchange of ions between the salt bath and the surface of the glass. Sodium irons are exchanged for potassium ions and that increases the strength of the glass.

Chemically strengthened glass is available in cylindrical, J-shaped, conical, spherical, toroidal, double-curvature and free-form shapes.