VITREOUS STATE: CHARACTERISTICS, EXAMPLES AND PROPERTIES - CHEMISTRY - 2025

The vitreous state occurs in bodies that have undergone rapid molecular ordering to take definite positions, generally due to rapid cooling. These bodies have a solid appearance with a certain degree of hardness and rigidity, although under the application of external forces they generally deform elastically.

Glass, not to be confused with glass, is used in the manufacture of windows, lenses, bottles, etc. In general, it has an infinite number of applications, both for domestic life and for research and technology; hence its importance, and the importance of knowing its properties and characteristics.

On the other hand, it is important to understand that there are different types of glass, both of natural and artificial origin. As for the latter, the different types of glass often respond to different needs.

Therefore, it is possible to obtain glasses that meet certain properties to meet certain technological or industrial needs.

characteristics

Regarding their optical characteristics, these vitreous bodies are isotropic (that is, their physical properties do not depend on direction) and transparent to most visible radiation, in the same way as liquids.

The vitreous state is generally considered as another state of matter beyond the three commonly known states, such as liquid, gas and solid, or new ones that have been discovered in recent decades, such as plasma or Bose condensate. Einstein.

However, certain researchers understand that the vitreous state is the result of a subcooled liquid or liquid with such a high viscosity that it ends up giving it a solid appearance without actually being one.

For these researchers, the vitreous state would not be a new state of matter, but rather a different form in which the liquid state appears.

Ultimately, what seems to be fairly certain is that bodies in the glassy state do not show a certain internal ordering, contrary to what happens with crystalline solids.

However, it is also true that on many occasions what is called an orderly disorder is appreciated. Certain ordered groups are observed that are spatially organized in a totally or partially random way.

Types of glasses

As mentioned above, glass can be of natural or artificial origin. An example of a naturally occurring vitreous body is obsidian, which is created by the heat present inside volcanoes.

On the other hand, both substances of organic origin and inorganic substances are liable to acquire a vitreous state. Some of these substances are:

- Different chemical elements, such as Se, Si, Pt-Pd, Au-Si, Cu-Au.

- Different oxides, such as SiO ₂, P ₂ O ₅, B ₂ O ₃ and certain of their combinations.

- Different chemical compounds, such as GeSe ₂, As ₂ S ₃, P ₂ S ₃, PbCl ₂, BeF ₂, AgI.

- Organic polymers, such as polyamides, glycols, polyethylenes or polystyrenes and sugars, among others.

Examples

Among the most common glasses that can be found, the following should be highlighted:

Vitreous Silica

Silica is an oxide of silicon, among which in general the best known is quartz. In general, silica is a fundamental component of glass.

In the case of quartz, a quartz glass can be obtained by heating it to its melting point (which is 1723 ºC) and proceeding to rapidly cool it.

Quartz glass has excellent resistance to thermal shock and can be bathed in water when it is red hot. However, its high melting temperature and its viscosity make it difficult to work with it.

This quartz glass is applied both in scientific research and in a multitude of applications for the home.

Sodium Silicate Glasses

Its manufacture is due to the fact that it offers properties similar to those of quartz glass, although sodium silicate glasses are much cheaper since to manufacture them it is not necessary to reach temperatures as high as in the case of quartz glasses.

In addition to sodium, other alkaline earth metals are added in the manufacturing process to provide the glass with certain particular properties, such as mechanical resistance, non-reactivity against chemical agents at room temperature (especially against water), among others.

Likewise, with the addition of these elements, it is also intended that they preserve transparency in the face of light.

Glass properties

In general terms, the properties of glass are related both to nature, as well as to the raw materials used to obtain it, and to the chemical composition of the final product obtained.

The chemical composition is usually expressed as percentages by mass of the most stable oxides at room temperature of the chemical elements that compose it.

In any case, some general properties of glass are that it does not lose its optical properties over time, that it is easily malleable when in the melting process, that its color depends on the materials that are added to it in the melting process and that they are easily recyclable.

Glass has the ability to reflect, refract and transmit light, thanks to its optical properties, without scattering it. Common glass has a refractive index of 1.5 which can be modified with different additives.

Similarly, common glass is corrosion resistant and has a tensile strength of 7 megapascals. Furthermore, the color of the glass can be modified by adding different additives.

Glass recycling

An important advantage of glass over other materials is both its ease of recycling and its unlimited recycling capacity, since there is no limit to the number of times the same glassy material can be recycled.

In addition, in the manufacture of recycled glass, energy savings are of the order of 30% with respect to the energy cost of its manufacture from raw materials. This energy saving, together with the saving in raw materials, ultimately also means significant financial savings.

References

1. Glass (nd). In Wikipedia. Retrieved on April 24, 2018, from es.wikipedia.org.
2. Amorphous solid (nd). In Wikipedia. Retrieved on April 24, 2018, from es.wikipedia.org.
3. Glass (nd). In Wikipedia. Retrieved on April 24, 2018, from en.wikipedia.org.
4. Elliot, SR (1984). Physics of Amorphous Materials. Longman group ltd.
5. The structure of glass is determined atom by atom. Experientia docet. April 24, 2018. Accessed February 1, 2016.
6. Turnbull, "Under what conditions can a glass be formed ?," Contemporary Physics 10: 473-488 (1969)