CORNING PYREX® 7740 BOROSILICATE

Pyrex® borosilicate glass has a very high resistance to attack from water, acids, salt solutions, halogens and organic solvents. It also has a moderate resistance to alkaline solutions. Only hydrofluoric acid, hot concentrated phosphoric acid and strong alkaline solutions cause appreciable corrosion of the glass.
Pyrex® glass has the following typical composition (percentage by weight):

SiO2	=	80.6%
B2O3	=	13.0%
Na2O	=	4.0%
AI2O3	=	2.3%

Coefficient of Expansion (20°C – 300°C)	3.3 x 10-6 K-1
Density	2.23 g/cm3
Refractive index (Sodium D line)	1.474
Dielectric Constant (1MHz,20°C)	4.6
Specific heat (20°C)	750J/kg°C
Thermal conductivity (20°C)	1.14W/m°C
Poisson's Ratio (25°C – 400°C)	0.2
Young's Modulus (25°C)	6400 kg/mm2

Pyrex® borosilicate glass has the ability to transmit light through the visible range of the spectrum and can be used effectively in the near ultra-violet range, making it ideally suitable for work in the field of photochemistry.

The graph above shows the degree of transmission of light as a function of wavelength in the ultra-violet, visible and infra-red sectors of the spectrum, for the thickness of glass generally encountered in laboratory ware (up to 5mm)

Refractive index (Sodium D line)	=	1.474
Visible light transmission, 2mm thick glass	=	92%
Visible light transmission, 5mm thick glass	=	91%

WHILE EVERY ATTEMPT HAS BEEN MADE TO VERIFY THE SOURCE OF THE INFORMATION, NO RESPONSIBILITY IS ACCEPTED FOR ACCURACY OF DATA.