A Glass is an amorphous solid (non-crystalline) substance ,which can be formed as it has a transition behavior from a hard and brittle solid to a liquid rubber material and vice versa.
This behavior is called the glass transition and are seen in amorphous or semi-crystalline materials range. About 1, 500 BC, glass bottles were used for the first time in Egypt.
The first glass is the glass that has emerged in nature, Especially in volcanic areas, Obsidian glasses may be used by people of the Stone Age and Due to resource constraints and because of the existence of need for cutting tools To spread throughout the world at that time, was traded.
However archaeologists believe that the first glass was probably made in the coastal region of today’s Syria, Mesopotamia or ancient Egypt.
Glass was made in about 3600 BC in Egypt. Windows did not pass the light themselves, because of they were non-existent they appeared colored.
The oldest glass was over found about half of the third millennium BC and probably it was emerged accidentally during the metal or pottery making.
The Glass remained as a luxury tool and Crashes and incidents that occurred at the end of the Bronze Age caused to stop the spread of glass.
Indigenous development of glass making began in about 1730 BC in South Asia.
In ancient China the production of glass had a later start unlike ceramic and metal. In the Roman Empire glass tools were found in the residential, industrial and funerals areas.
Glass was used extensively in the Middle centuries. In the archaeological carvings that was carried out across the UK there was found Anglo-Saxon in the cemeteries and residential areas. In the Anglo-Saxon period to produce a series of household Appliances such as windows, kitchen pottery and even decorative accessories was used the glass. From the 10th century onwards colored glass was used for windows of the ordinary and comprehensive churches . Basilica church of St. Daniel and Chartres Cathedral church are two well-known examples of this use.
AD 14th century, architects began to use colored glass for buildings such as building san-shill in Paris (1203 to 1248), with the beginning of the Renaissance
Usage of big stained glass windows were reduced and it’s use had grew in people’s houses. With the advancement of knowledge and technology the glasses became cheaper and its use more universal , it was possible to produce inexpensively them in large formats.
In the 19th century AD along with the new Gothic architecture stained (colored) glass was a new look. In the 20th century a new species for layered glass, concrete (retrofitting) and brick came to the market that the use of glass in construction had increased. Multi- storey buildings had curtains on them that almost of them were made by glass more than walls.
At the beginning because of the lack of reaction with water ,the glass had a container usage. But at the end of the century its optical Features were considered and lens manufacturing, medical devices and instruments of astronomy was spread .
In the 19th century the ancient methods of production of glass especially embossed glass changed its appearance. This changed method was created for the first time since the Roman Empire and was seen more in neoclassical designs.
The Art Nouveau movement of the glass was used a lot. Over time, little by little, small workshops of art glass was everywhere.
Silicate glass and its application
Most of silicate glasses are Transparent and so that have many uses. they can be noted in many applications including the construction industry and glass doors and windows. Although most of them can are used to cover other substances because it can take any shape. Another use of the glass is traditional use as bowls, vases, bottles and so on. If the glass is more rigid then they can be used in marble production, beads and decorative glasses.
The glass can be fragile or light-reflecting these features can be achieved by cutting or polishing and can be used in production of lenses, prisms or crystal containers.
Besides With the help of metal salts can give color or be colored glass. This ability can be cause a lot of artwork and stained glass windows. Although glass is very fragile but at the same time it’s very stable .Age of some kind of glass that was found, dates back to the early production of glass.
The Silicon dioxide (a chemical compound SiO2) is the most basic Glass manufacturer. In nature, the effect of a lightning strike with sand occurs reaction of quartz glass condensation in which a structure made of hollow (tubular) root-like, called Thunderstone arises. Silica glass that is made primarily from silica having a transition temperature above 1200 ° C is required for special applications
But does not apply to public , That’s why some other raw material mixture are added to get it easier in Manufacturing process , One of these ingredients is sodium carbonate that lowers the glass transition temperature.
Sodium carbonate makes the glass soluble in water, To avoid these features of lime that is obtained from limestone. By adding magnesium oxide (MgO) and alumina the glass gets more stable. Finally glass is made from 70 to 74 weight percent silica. lime glass is called soda, These glass covers 90% of the glass.
More available glasses have also other raw materials to change slightly the properties of some species, for example crystal glass and other kind of crystal,
Unlike ordinary glass these are more brighter because they have refractive index , light dispersion and higher reflection.by Adding barium increases the refractive index. thorium dioxide makes low the optical dispersion of high refractive index of glass, In the past, this type of glass was used in the manufacture of high-quality lenses, But it was stopped due to nuclear decay and was replaced by lanthanum oxide. Adding iron to the glass causes the glass to absorb infrared energy.
This feature of filters that must absorb heat like spotlights is required filming.
Also the cerium oxide (IV) makes the glass to absorb ultraviolet wavelengths.
The glass in Iran
The oldest glass in Iran belongs to the second millennium BC .Glass Samples of the second millennium to the time of BC includes the scent bottle , bangles, statues, bowls and multiple straits that have been obtained .In the chaghzanbil
excavations of prehistoric periods glass bottles have been found, which indicates the abundance of glass in ancient Elam. Marlik civilization that is dated 3400ago , pieces of glass have been found, also were found the glass containers that are for dairy use in Lorestan excavations. Since the Achaemenid dynasty the glass works were limited. In that period old glass beads of iran which apparently was black and white was famous around the world. Sassanid artists have special skills in cutting the glass. Sasanian glass was highly valued in china especially blue glass was Considered precious .Leggy cups with leading circles of the Parthian and Sassanian period remains in place.
Glass containers of Islamic period are under the impact of Designs before Islam.
In the Seljuk period and until the Mongol invasions beautiful glass tools and containers came out from Glassblowing furnace in Gorgan which have been carved sometimes in enamel type and sometimes as thin as a paper.
In Seljuk era in Iran there was a peak of glassblowing industry. Glass products of this time include large and small containers , delicate scent bottles, cups and pots of various sizes and forms and decorative objects in the small animals shapes etc.
Glass making boom was disappeared in Mughal era and instead pottery and tile work have been Flourished. In the Timurid period glassblowing Promoting was noteworthy.
Glass makers have come from Egypt and Syria to Iran and also similar glasses of Iran were sent in Egypt and Syria , During this period there were two major centers of glass making in two cities of Iran shiraz and samarghand.
From this time onwards This art was on the decline since the institution of the reign of Shah Abbas when by creating lights of the mosque and bottle the art has come alive .shah abbas had brought Venetian Glass Blowers in Iran in order to revive the industry. As a result glassblowing had rebounded in the Safavid period.
Sometimes glass was made by blowing into the form and sometimes glass was carved to get the jewelry shape and carving designs on it and sometimes the glass was with sparkling motifs, enamel and gold.
In this period glass making workshops in various cities of Iran including Isfahan, Shiraz and Kashan were established. In the distance between the Safavid and Qajar dynasty Glassblowing Craft in Iran from the aspect of evolution had not progress and By the end of the Qajar dynasty gradually had been weaker.
With the arrival of cheaper-quality glass to the market, the industry began to decline entity.