soda-lime glass
Soda-lime glass is the most prevalent type of glass. It can be processed so inexpensively
that it is used for windowpanes and bottles.
Soda-lime glass can be created by melting a mixture of silicon dioxide, sodium carbonate, and either calcium carbonate or calcium oxide. Adding sodium carbonate lowers the melting point of the glass, thus lowering the energy required to heat it, but also making it soluble in water. Calcium carbonate or calcium oxide are added to counter this.
In soda-lime glass, sodium (Na+) and calcium (Ca2+) ions are inserted into the silicate ion structure such that the tetrahedrons of silicon and oxygen atoms are stretched. The glass transition temperature (Tg) is about 730°C and the melting point is about 1000°C.
Water containing powders of soda-lime glass exhibits alkalinity because Na+ and Ca2+ dissolve in it, leading to hydrolysis.
A flame test of soda-lime glass reveals colors consistent with the mixing of its constituents, intermediate between those of Na+ and Ca2+.
Principal uses
Mirrors, microscopic slides, touch screens, filters, photomasks, glass masters, data storage disks, printed circuit substrates, photographic plates, substrates, light bulbs, wafers and optical windows,ceramics.
Typical thermal/mechanical properties
Thermal Conductivity: 0.937 W·m/m²K
Density (at 20º C/68 ºF): 2.44 g/cm³
Hardness (Mohs Scale): 6–7
Knoop Hardness: 585 kg/mm2 + 20
Modulus of Elasticity (Young's): 7.2 x 1010 Pa
Modulus of Rigidity (Shear): 3.0 x 1010 Pa
Bulk Modulus: 4.3 x 1010 Pa
Poisson's Ratio: 0.22
Specific Gravity: 2.53
Specific Heat: 0.21
Specific Weight: 2,483 g/cm³
Thermal Coefficient of Expansion (0/300 °C): 8.6 x 10-6/°C
Softening Point: 726°C/1340°F
Annealing Range: 546°C/1015°F
Strain Point: 514°C/957°F
Failure Strength: 70 MPa/10,000 psi
Typical optical properties
See also
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