Glass Window Repair Chicago

The composition of the glass

The composition of the glass

Some elements such as Silicon and boron can form a glass by single combination with oxygen (oxide of...) and rise to a high temperature. These oxides are called oxides trainers because they form the skeleton of the glass. Combined with other so-called "modifiers" which are:

Fluxes which lowers the melting temperature of the trainers oxides (silica = 1730 ° C).

The stabilizers that alter the physical properties of the glass diminished by the addition of the fondant.

Trainers oxides (vitrifiants)

Silica: (silicon dioxide SiO2)

It is the main component of the glass which represents approximately 70% of the mass. It is the trainer's network.More Info If it increases its quantity, increase the hardness of the glass. Its melting point is at 1730 ° C. It enters the manufacture in the form of sand which the purest contain 99.5% (quartz sand). The sand from Fontainebleau, its quality, is highly sought after for the manufacture of optical and Crystal glasses. The percentage of silica is high and more the coefficient of expansion is low; Therefore, more glass is resistant.

Boric anhydride: (boron or borax anhydrous B2O3)

It reduces the coefficient of expansion and improves resistance to thermal shock; It is also more resistant to water. Its melting point is at 2300 ° C. It is used for laboratory work (heat-resistant glass such as Pyrex). It also has the properties of a fudge.

Phosphoric anhydride: (P2O5 phosphorus)

Employee in the field of optics. The main source in the middle ages is the wood ash.

Modifying oxides

Fluxes: (alkali oxides)

The silica to get a drink, but its melting point is very high (1730 ° C). Adding fluxes, lowering this temperature 1400 ° C (energy saving) and it facilitates job opportunities. The fluxes sodium and potassium were used jointly from the middle age.

Sodium oxide (Na2O soda): he once entered the composition in the form of ashes of marine plants (ex: la salicorne) or nitre (Greek = nitron). It lowers the melting point, increases the brightness of the glass and its resistance to atmospheric agents and the coefficient of expansion. It is used more for industrial glass for the glass blowing because it must be constantly heated when shaping.

Potassium oxide (K2O): he once entered the composition in the form of terrestrial plants as the fern ashes; Today, it uses of saltpeter (potassium nitrate KNO3). It lowers the melting point, increases the brilliance of the glass and makes it soft to the size, but it decreases its chemical resistance. It advantage glass-blowing because it increases the working time during the shaping.

Magnesium oxide (MgO): it is used in the form of dolomite (calcium + magnesium). It is not necessary for all lenses, except the float glass, glass to glass and tableware. It lowers the melting temperature and increases the resistance to chemical agents.

Stabilizers: (alkaline earth oxides)

The introduction of an alkaline oxide (melting) resulted in the rupture of a Si - 0 link and the appearance of oxygen "not connecting". This has the effect of weakening the network and increase the solubility in water.

Calcium oxide (CaO): lies in the form of lime (which is the most used stabilizer) and dolomite (when the glass must contain magnesia). It increases the chemical resistance of glass, its brightness and decreases its solubility, but in excess it causes a devitrification. It was used in the middle age for sodium glasses.

Zinc oxide (ZnO): it increases the brightness and elasticity.

Iron oxide (Fe2O3): (this is a stabilizer and a dye) often contained in natural rocks, it gives a greenish tint. Therefore, proceed to a discolouration of this shade. To do this, you can add manganese (MnO2) dioxide (SOAP of the glass).

Lead oxide (PbO): enters the composition of the Crystal. Glass Window Repair It also lowers the melting point by stabilizing the composition. It makes brighter glass giving it a slight yellowish tinge, it is easier to cut and work.


The glasses are often dyed in the mass; This means that adding metallic oxides during the merge. They come in very small proportion of the mixture (ex: copper oxide for green).

Colouring in mass is due to the presence in the glass of transition metal ions.