Glossary / Fused Silica Quartz

Fused Silica Quartz

What is Fused Silica Quartz?

Fused silica quartz is an industrial raw material that is used to make many types of scientific items for applications such as  spectrophotometer cuvettes, fluorometer cuvettes, flow channel cells, quartz microfluidic chips, and many other optical products used for flow cytometers and particle sizers. 

Fused silica quartz can also be used to manufacture refractory shapes due to the fact that the fused silica quartz material has great thermal shock resistance and are extremely stable to most chemical elements and compounds.  Fused silica quartz can handle high concentration of acids and not be affected.  The only acid that does effect the fused silica would be hydrofluoric acid.  Even in low concentrations this would have a negative effect on the material. Flow channel cuvettes made from fused silica are frequently used for applications such as flow cytometry, particle counting, particle sizing, and other various applications.

Fused quartz  and  fused silica quartz are forms of  glass  that are mostly made up of silica  in  it's non-crystalline form. They are manufactured using several different processes. The quartz formed by heating the material to it's melting point and rapidly cooling it (called splat-quenching or melt-quenching) are referred to as vitresous.  This term is the same as using the word glass, for example glass quartz. Fused Silica is produced by fusing high purity silica in a special furnace. This procedure is done at extremely high temperatures, over 1,000 degrees Fahrenheit.

Fused Silica Quartz Refractive Index Properties

The fused silica material has an absolute refractive index (ARI), measured at a wavelength of 193.368 nm, of up to about 1.560835. In another embodiment, the absolute refractive index  of the fused silica quartz article is less than or equal to about 1.560820. In a third embodiment, the absolute refractive index of the fused silica article is less than or equal to 1.560815. In a fourth embodiment, the fused silica quartz article has an ARI of less than or equal to 1.506810.  IR grade Fused Silica is a super purity synthetic fused silica material.  IR Quartz is manufactured by melting of highly pure ashes in vacuum. It is transparent in the ultraviolet, visible and infrared spectral regions. It has no absorption bands in the visible region and has no OH absorption band at 2700 nm ("water band").

It is known that laser-induced degradation adversely affects the performance of fused silica quartz optical members by decreasing light transmission levels, altering the index of refraction, altering the density, and increasing absorption levels of the glass. Over the years, many methods have been suggested for improving the optical damage resistance of fused silica glass. It has been generally known that high purity fused silica prepared by such methods as flame hydrolysis, CVD-soot remelting process, plasma CVD process, electrical fusing of quartz crystal powder, and other methods, are susceptible to laser damage to various degrees.

What is Synthetic Fused Silica Quartz?

Made from a high concentration of silicon-rich chemicals, synthetic fused silica quartz is often formed using a ongoing fire hydrolysis process.  This process involves chemical gasification of silicon, oxidation of this gas to silicon dioxide, and thermal fusion of the resulting dust (although there are alternative processes). The outcome of this process is a transparent quartz glass material with a super high purity and the best optical transmission in the deep UV aka ultraviolet, also known as the far ultraviolet range. One method involves adding silicon tetrachloride to a hydrogen-oxygen flame.  A hydrogen oxygen flame produces a highly intense flame that can easily melt the quartz and ensures the quartz fuses properly.