Pyrex 7740

Pyrex^® 7740 is a low expansion borosilicate glass. We carry many different forms of Pyrex^® glass: Tubing, Rods, flat polished and rolled sheet glass, Jars, Cylinders, annular edge sight glass, Tubular gage glass, IRR coated and more. Pyrex glass is good for normal use temperature of 446 degrees F and maximum use temperature 914 degrees F. Pyrex^® can be tempered to increase its mechanical strength. The flat polished sheets are used for sight glasses, windows, etc. The flat rolled sheets in the thinner sizes are fine for non critical window, fireplace, lighting applications, while the thicker sheets are used for blanks to be ground and polished or in architectural applications where its high resistance to weathering, acids and the surface rolled look is desired.

Glass Code: Corning Pyrex^®		7740
Type		Borosilicate
Color		Clear
Principal Use		General Lab ware
Thermal Expansion Multiply by 10^-7cm/cm/°C	0 - 300°C.	32. 5
Thermal Expansion Multiply by 10^-7cm/cm/°C	25°C. to setting point	35
Upper Working Temp. for annealed glass (Mechanical considerations only)	Normal service °C.	230
	Extreme service °C.	490
Upper Working Temp. for tempered glass (Mechanical considerations only)	Normal service °C	260
	Extreme service °C.	290
Thermal Shock Resistance (15x15cm annealed plates) This data is approx.	3.2mm Thick °C	160
	6.4mm Thick °C	130
	12.7mm Thick °C	90
Thermal Stress Resistance °C.		54
Viscosity Data (These data are subject to normal manufacturing variations.)	Strain point °C.	510
	Annealing point °C.	560
	Softening point °C.	821
	Working point °C.	1252
Density g/cm³		2. 23
Young's Modulus (multiply by 10³Kg/mm²)		6.4
Poisson's Ratio		. 20
Log₁₀ of Volume Resistivity ohm/cm.	25°C	15. 0
	250°C	8. 1
	350°C.	6.6
Dielectric Properties (1 MHz 20°C)	Power factor %	0. 50
	Dielectric constant	4. 6/td>
	Loss factor %	2. 6
Refractive index		1. 474
Stress-Optical Coefficient, (nm/cm)/(Kg/mm²)		394