Difference Between Quartz and Glass Cuvettes

Difference Between Quartz and Glass Cuvettes
What is the difference between quartz and glass cuvettes?

One of the most common questions in the cuvette world is, "What is the difference between quartz and glass cuvettes?"  We're going to explain the differences and put this question to rest once and for all.

The biggest difference between quartz and glass is the transmission properties.  Quartz or quartz glass is as the name implies, a glass material but it is very difference than a "glass cuvette".  When people look for a "glass cuvette" the industry standard is Optical Glass which is usually a standard B270 otherwise known as Optical Crown Glass.  For the sake of this article when we refer to, "glass", it means Crown Glass and when we refer to, "Quartz", it means Synthetic Quartz.

Crown Glass

Crown glass is produced from alkali-lime (RCH) silicates containing approximately 10% potassium oxide. It has low refractive index (≈1.52) and low dispersion (with Abbe numbers around 60); crown glass is one of the earliest low dispersion glasses.

As well as the specific material named crown glass, there are other optical glasses with similar properties that are also called crown glasses. Generally, this is any glass with Abbe numbers in the range 50 to 85. For example, the borosilicate glass Schott BK7 is an extremely common crown glass, used in precision lenses. Borosilicates contain about 10% boric oxide, have good optical and mechanical characteristics, and are resistant to chemical and environmental damage. Other additives used in crown glasses include zinc oxide, phosphorus pentoxide, barium oxide, fluorite and lanthanum oxide.

Quartz Glass, Fused Silica, Fused Quartz, and Synthetic Fused Silica

Fused quartz and fused silica are varieties of glass containing primarily silica in amorphous (non-crystalline) type. They are manufactured using many distinct processes. Note that glasses formed by the traditional 'melt-quench' methods (heating the substance to melting temperatures, then rapidly cooling to the solid glass phase), are often referred to as 'vitreous', as in 'vitreous silica'. The term 'vitreous' is synonymous with 'glass', when utilized inside the melt-quench context.

Fused quartz is manufactured by melting naturally occurring quartz crystals of large purity at approximately 2000 C, working with either an electrically heated furnace (electrically fused) or a gas/oxygen-fuelled furnace (flame fused).  Fused quartz is usually transparent. The optical and thermal properties of fused quartz are superior to those of other kinds of glass because of its purity. For these reasons, it finds use in situations for example semiconductor fabrication and laboratory equipment. It has better ultraviolet transmission than most other glasses, and so is used to make lenses and other optics for the ultraviolet spectrum. Its low coefficient of thermal expansion also makes it a helpful substance for precision mirror substrates.

Fused quartz can also form naturally. The naturally occurring form is a metamorphic rock known as quartzite. An increase in heat causes the crystals inside the quartz to turn out to be fused together. An important distinction is that quartzite isn't necessarily an amorphous form.

Fused silica is produced employing high-purity silica sand as the feedstock, and is generally melted utilizing an electric furnace, resulting in a very substance which is translucent or opaque. (This opacity is caused by really little air bubbles trapped within the material.)

Synthetic fused silica is made from a silicon-rich chemical precursor generally working with a continuous flame hydrolysis process which includes chemical gasification of silicon, oxidation of this gas to silicon dioxide, and thermal fusion of the resulting dust (even though you'll find alternative processes). This results in a very transparent glass with an ultra-high purity and enhanced optical transmission inside the deep ultraviolet. 1 prevalent technique involves adding silicon tetrachloride to a hydrogen-oxygen flame, even so use of this precursor final results in environmentally unfriendly by-products including chlorine and hydrochloric acid. To eliminate these by-products, new processes have been developed employing an alternative feedstock, which has also resulted in a very higher purity fused silica with further improved deep ultraviolet transmission.

Precision Cells cuvettes are made with Synthetic Fused Silica, this is our ES Quartz.  For IR Quartz Cuvettes we also use a highly pure synthetic material known as ED-C quartz.

The Differences

Major differences between a "glass" material and a "quartz" material:
  • Transmission Properties- Transmission properties of quartz are far superior.
  • Thermal Features - Quartz has a much higher melting point than glass.
  • Chemical Compatibility - Quartz has a very different chemical structure than glass making it able to handle a broader range of chemicals that a glass cuvette can not accommodate.
  • Modifications - Glass cuvettes, especially Pyrex glass, are easier to make modifications to than quartz.
Material Code: G Standard Glass Material: B270, optical crown glass
Specification Value Units
Refractive Index 1.5251 ne at 546nm
1.5230 nd at 588nm
Density 2.55 g/cm3
Modulus of elasticity E=71.5 103 N/mm2
Coefficient of Thermal Expansion 95 x 10-7/K temperature range = 20-300oC
Useable optical range 334 to 2500 nanometers

Material Code: PX Pyrex Material: Borosilicate
Specification Value Units
Refractive Index 1.473 nd at 587.6nm
Density 2.23 g/cm3
Modulus of elasticity E=64 103 N/mm2
Coefficient of Thermal Expansion 33 x 10-7/K temperature range = 20-300oC
Useable optical range 320 to 2500 nanometers

Material Code:  Synthetic Quartz Material: UV Quartz
Specification Value Units
Refractive Index 1.551 200nm
1.506 254nm
1.488 300nm
1.470 400nm
1.458 600nm
1.450 1000nm
Density 2.2 g/cm3
Modulus of elasticity 73x106 Kpa
Coefficient of Thermal Expansion 5.3 x 10-7/K temperature range = 0-1000oC
Useable optical range 170 to 2700 nanometers