Low rainfall glass. Graduated and peaked. Made from LBG 3.3 borosilicate glass. Conforms to DIN 12331, ISO 3819 LBG 3.3 is a borosilicate glass with a minimum silica content of 80% and very low expansion coefficient (3,310-6 K-1) belonging to the group of borosilicate type “3.3” as defined in ISO 3585. It is used in products where chemical resistance, mechanical resistance and resistance to sudden changes in temperature should be combined, and because of this unique combination of properties it is the type of reference glass with which most laboratory products are manufactured. Physical and chemical properties Linear Expansion Coefficient (@ 20/300 oC): 3,310-6 K-1 Retriction Temperature (Strain point): 520 oC Ripening temperature (Annealing point): 560 ± 10 oC Softening temperature (softening point): 820 ± 10 oC Density: 2.23 ± 0.02 g/cm3 Hydrolitic resistance (according to ISO 719, water 98 oC): Class 1 Hydrolitic resistance (according to ISO 720, water at 121 oC): Class 1 Acid resistance (according to ISO 1776): Class 1 Alkalis resistance (according to ISO 695): Class 2 Typical composition 80.4% by weight SiO2 13.0% by weight B2O3 4.2% by weight Na2O 2.4% by weight Al2O3
