devitrification

For more information on devitrification as an artistic technique, see the main article above.

Marsh showed that in some glasses there is incipient devitrification even when they are new.

In some cases, devitrification begins at centres scattered regularly throughout the whole mass, and this can produce very attractive effects.

Since devitrification involves shrinkages, the glass is often weakened and sometimes falls to pieces in the process.

This change is called devitrification; it is common in glasses, as these are essentially unstable.

Devitrification is the process of crystallization in a formerly crystal-free (amorphous) glass.

It also can cause undesirable effects such as unattractive discoloration, bubbling, or devitrification.

Such textures may document solid-state devitrification of glass.

This is known as devitrification.

Still, the rock layer here contains five to 30 percent phenocrysts, and has high levels of devitrification and lithic content.

While this condition is normally undesired in glass art, it is possible to use devitrification as a deliberate artistic technique.

Devitrification is the process of converting glass into a crystalline substance by heating it to a temperature just below its melting point then cooled.

Graphic texture is commonly created by exsolution and devitrification and immiscibility processes in igneous rocks.

Causes of devitrification, commonly referred to as "devit", can include holding a high temperature for too long, which causes the nucleation of crystals.

The term "devitrification" is used by archaeologists and art historians to refer to a glass object which has lost it vitreous nature, giving the glass a weathered appearance.

It commonly occurs as a devitrification product of volcanic glass shards in tuff and as vesicle fillings in basalts, andesites and rhyolites.

The chemical compositions of some types of glass can make them more vulnerable to devitrification than others, for example a high lime content can be factor in inducing this condition.

Moje was looking for a glass manufacturer that could make a wide palette of colored glass but also help with the incompatibility and devitrification problems that he was experiencing.

They can then be cut in thin sections (40 to 200 nm thick) with a diamond knife in a cryo ultramicrotome at temperatures lower than -135 C (devitrification temperature).

Devitrification can occur in fiberglass (glass wool) batting or blown-in insulation where it can result in the product becoming a powder with substantially lower thermal insulation properties.

In a general sense, any crystallization from a magma could be considered devitrification, but the term is most commonly used for the formation of spherulites in otherwise glassy rocks such as obsidian.

Techniques for avoiding devitrification include cleaning the glass surfaces of dust or unwanted residue, and allowing rapid cooling once the piece reaches the desired temperature, until the temperature approaches the annealing temperature.

Devitrification is almost universal in ancient glasses which were usually badly made in the first place and have had plenty of time to crystallize; the result, however is, often very beautiful, though these old glasses have become very weak.

In the ancient rocks of Wales, Charnwood, the Pentland Hills, etc., similar tuffs are known, but in all cases they are greatly changed by silicification (which has filled them with opal, chalcedony and quartz) and by devitrification.

Typical alteration textures associated with devitrification of submarine volcanic rocks such as rhyolitic glasses, notably formation of spherulites, of perlite, lithophysae, and low-temperature prehnite-pumpellyite facies sub-seafloor alteration is ubiquitous though often overprinted by later metamorphic events.