AR-GLAS / Physical and Chemical Properties
- Introduction | Tubing | Rod | Properties -  AR-Glas Catalogue
Soda lime 9.1 

Physical Data
Mean coefficient of linear expansion a (20 ºC;300 ºC) acc. to ISO 7991
9.1 ˇ 10-6 K-1
Transformation temperature Tg
525 ēC
Temperature fixed points at viscosity h in dPa ˇ s:
          1013 upper annealing point
530 ēC
          107.6 softening point
720 ēC
          104 working point
1040 ēC
Density r at 25 ºC
2.50 g ˇ cm-3
Modulus of elasticity E (Young's modulus)
73 · 103 N · mm-2
Poisson's ratio m
0.22
Thermal conductivity lw at 90 ºC
1.1 W · m-1 · K-1
Temperature for the specific electrical resistance of 108 W · cm
(DIN 52 326) tk 100
200 ºC
Logarithm of the electric volume resistance (W · cm)
          at 250 ºC
7.1
          at 350 ºC
5.7
Dielectric properties (1 MHz, 25 ºC)
          Dielectric figure (permittivity) e
7.2
          Dielectric loss factor (dissipation factor) tan d
70 · 10-4
Refractive index nd (l = 587.6 nm)
1.514
Stress-optical constant (DIN 52 314) K
2.7 · 10-6 mm2 · N-1
   

Resistance to Thermal Shock
Resistance to thermal shock is not an exact, by defined physical quantity (for more details see ISO 718); it depends on the measuring method, the shape, the wall thickness and the surface and end properties of the glass object in question. Rapid temperature changes cause high temporary stress in the glass, meaning that rapid cooling processes are very dangerous, since in this case a thin outer layer of the glass is placed under tensile stress over the still hot inner core. Glass is much more susceptible to tensile stress than to compressive stress.
The following graph shows the resistance to thermal shock of the tubes Duran, Durobax, Fiolax Clear, Fiolax Amber, Illax and AR-Glas:
   

Chemical Composition (main components in approx. weight %)
SiO2
B2O3
K2O
Al2O3
Na2O
BaO
CaO
MgO
69
1
3
4
13
2
5
3
   

Chemical Data
Hydrolytic Class (ISO 719)
HGB 3
Acid Class (DIN 12116)
Class S 1
Alkali Class (ISO 695)
Class A 2
   

Transmission (%)
AR-Glas Transmission

Wavelength (nm)
* Measured on processed glass with a wall thickness = 1 mm
   

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