Chemical Properties

Note on Sodium / Alkali Leaching:

All soda-lime type glasses and some borosilicate glasses contain sodium or alkali metal ions. Prolonged exposure to liquids or vapor, such as water, will cause the sodium / alkali ions to migrate to the surface of the glass. This can cause cloudiness or haze on the surface of the glass. Porous coatings may also incur this phenomenon, causing a disruption of the bond between the coating and the glass surface. In high humidity or critical surface applications, this must be considered when specifying the material. Placing a "barrier" coating, such as silicon dioxide on the glass will limit the amount of reaction.

Acid Resistance (SR) per ISO 8424:1987 - Large quantities of a strong acid (pH 0.3) are applied at 25°C. The time to remove a layer of 0.1 mm thick is measured and classified by SR values.

Alkali Resistance (AR) - The test occurs with large quantities of a warmed (50°C) alkali solution (pH 12). The time required to remove a layer of 0.1 mm is used to designate four alkali resistance classes AR1 to AR 4.