Borosilicate
glass is a type of glass with the main glass-forming constituents silica and boron oxide. Borosilicate glasses are known for having very low coefficients of thermal expansion (~5 × 10−6 /°C at 20°C), making them resistant to thermal shock, more so than any other common glass. Such glass is less subject to thermal stress and is commonly used for the construction of reagent bottles.

History
Borosilicate glass was first developed by German glassmaker Otto Schott in the late 19th century[1] and sold under the brand name "Duran" in 1893. After Corning Glass Works introduced Pyrex in 1915, it became a synonym for borosilicate glass in the English-speaking world. The European manufacturer of Pyrex, Arc International, uses borosilicate glass in its Pyrex glass kitchen products;[2] however, the U.S. manufacturer of Pyrex kitchenware uses tempered soda-lime glass.[3] Thus Pyrex can refer to either soda-lime glass or borosilicate glass when discussing kitchen glassware, while Pyrex, Bomex, Duran and Kimax all refer to borosilicate glass when discussing laboratory glassware. Most borosilicate glass is colorless. Colored borosilicate, for the studio glass trade, was first widely brought onto the market in 1986 when Paul Trautman founded Northstar Glassworks.[citation needed] In 2000, former Northstar Glassworks employee Henry Grimmett started Glass Alchemy and developed the first cadmium Crayon Colors and aventurine Sparkle colors in the borosilicate palette. In addition to the quartz, sodium carbonate, and calcium carbonate traditionally used in glassmaking, boron is used in the manufacture of borosilicate glass. Typically, the resulting glass composition is about 70% silica, 10% boron oxide, 8% sodium oxide, 8% potassium oxide, and 1% calcium oxide (lime). Though, somewhat more difficult to make than traditional glass (Corning conducted a major revamp of their operations to make it), it is economical to produce; its superior durability, chemical and heat resistance finds excellent use in chemical laboratory equipment, cookware, lighting and, in certain cases, windows.

Manufacture Process
Borosilicate glass is created by adding boron to the traditional glassmaker's frit of silicate sand, soda, and ground lime. Since borosilicate glass melts at a higher temperature than ordinary silicate glass, some new techniques were required for industrial production. Borrowing from the welding trade, burners combining oxygen with natural gas were required.

Composition and physical characteristics
Borosilicate glass has a very low thermal expansion coefficient, about one-third that of ordinary glass. This reduces material stresses caused by temperature gradients, thus making it more resistant to breaking. This makes it a popular material for objects like telescope mirrors, where it is essential to have very little deviation in shape. It is also used in the processing of high-level radioactive waste, where the waste is immobilised in the glass through a process known as vitrification (contrast with Synroc). The softening point (temperature at which viscosity is approximately 107.6 poise) of type 7740 Pyrex is 820 °C (1,510 °F).[4] Borosilicate glass is less dense than ordinary glass. While more resistant to thermal shock than other types of glass, borosilicate glass can still crack or shatter when subject to rapid or uneven temperature variations. When broken, borosilicate glass tends to crack into large pieces rather than shattering (it will snap rather than splinter).

Lampworking
Borosilicate, or "boro" as it is often referred to, is used extensively in the glassblowing process lampworking, which involves using a burner torch to melt and form glass, using a variety of metal and graphite tools. Borosilicate is referred to as "hard glass" and has a higher melting point than "soft glass" which is used in glassblowing formed in large furnaces and large rods. Raw glass used in lampworking comes in glass rods for solid work and glass tubes for hollow work tubes and vessels/containers. Lampworking is used to make complex and custom scientific apparatus; most major universities have a lampworking shop to manufacture and repair their glassware. For this kind of "scientific glassblowing", the specifications must be exact and the glassblower must be highly skilled and precise. Lampworking is also done as art and common items made include goblets, paper weights and pendants. " source - http://en.wikipedia.org/wiki/Borosilicate_glass All things mesh like notes in a song to create a symbiosis greater than that of the parts separate.