Technical Data

Borosil Low Expansion Borosilicate Glass

From the 16 Century to today, chemical research teams have used glass containers for a very basic reason : the glass container is transparent, almost invisible. And so the contents and the reaction are clearly visible.But because chemists must heat, cool and mix chemical substances, ordinary glass is not always adequate for laboratory work. Laboratory work requires apparatus made in a glass which can readily be moulded into any desired shape or form, which offers maximum inertness when in contact with the widest range of chemical substances, which can withstand thermal shock without fracture and high temperature work without deforming, and which will be resilient enough to survive the everyday knocks to which it will be subjected in normal laboratory handling, washing and sterilizing processes. is the trade name of such a glass. Items represent optimum mechanical, thermal and chemical behaviour. This glass is used in laboratories as well as for industrial applications where maximum thermal resistance, thermal shock resistance, mechanical resistance as well as unusual chemical resistance are required

Chemical Composition

glass is a low alkali borosilicate Type 3.3 glass. Its typical chemical composition is given below. It is virtually free of magnesia-lime-Zinc group and is completely free of arsenic and other heavy material. Approx % by weight SiO 81 2 B O 13 2 3 Na O / K O 4 2 2 Al O 2 2 3

Thermal Properties

As the Coefficient of thermal expansion of glass is low, the thermal stresses under a given temperature gradient are consequently low and the glass can withstand higher temperature gradients and also sudden temperature changes / thermal shocks. Minute scratching of glass surface can however reduce its thermal resistance. In general “Strain Point” should be regarded as the maximum safe operating temperature of glassware. When 0 heated above 500 C the glass may acquire permanent stresses on cooling All labware is annealed in modern Lehr ovens under strictly controlled conditions to ensure minimal residual stress in the products. The typical thermal properties of glassware are given below : Coefficient of Linear Expansion 32.5 x10 / C 0 Strain Point 515 C 0 Annealing Point 565 C 0 Softening Point 820 C Specific Heat 0.2 3 0 Thermal Conductivity (Cal / cm / C / sec) 0.0027

Chemical Durability

is highly resistant to water, neutral and acid solutions, concentrated acids and their mixtures as well as to chlorine, bromine, iodine and organic matters. Even during extended 0 period of reaction and at temperatures above 100 C, its chemical resistance exceeds that of most metals and other materials. It can withstand repeated dry and wet sterilization without surface deterioration and subsequent contamination. Resistance to attack of various chemicals is shown below. Only hydrofluoric acid, very hot phosphoric acid and alkaline solutions increasingly attack the glass surface with rising concentration and temperature. Contact chemical Duration Loss in Wt 2 In Hr mg / m 0 Water distilled at 100 C 6 10 0 Water Vapour Steam at 121 C 1 75 Acid HCI 6 100 0 80% H SO at 130 C 12 140 2 4 Alkali-1N soln. of Na CO boiling 6 4000 2 3 Infusion Fluids Isotonic 0 NaCI (0.85%) 121 C 2½ 70 0 Glucose (5%) 121 C 2½ 50

Fabricating With Borosil Glass

Due to low expansion of glass and easy workability, this glass can be shaped, formed, joined into complicated apparatus. It can be done even by an analyst in his own laboratory and keep on changing till he gets what he needs. In case where annealing in a controlled oven is difficult he can do so by flame annealing which is also a great advantage.

Optical Properties

Laboratory glassware made from glass show no noticeable absorption in the visible region of the spectrum. It appears consequently clear and colourless. -7 0

Products

• Laboratory Glassware
• Liquid Handling System
• Disposable Plastic