4. Chemical Properties

There are some glasses that lack durability. This is due to the chemical behaviour of certain constituents utilized in the composition.

Such glasses can be affected by water vapour, acid, gases, etc., as well as ions in the polishing slurry. As a consequence, dimming and staining may appear on the surfaces of these glasses during processing and storage.

Since such phenomena have to do with surface conditions and environment, no single test can be accepted as a criterion of durability under all conditions.

We have listed resistance to water and acid by the powder test method and resistance to weather by the surface test method. We have also listed resistance to acid and phosphate in accordance with the test methods prescribed in ISO8024 and ISO9689.