title: List of physical properties of glass
text: # List of physical properties of glass
  
  This is a list of some physical properties of common glasses. Unless otherwise stated, the technical glass compositions and many experimentally determined properties are taken from one large study. Unless stated otherwise, the properties of fused silica (quartz glass) and germania glass are derived from the SciGlass glass database by forming the arithmetic mean of all the experimental values from different authors (in general more than 10 independent sources for quartz glass and $T_g$ of germanium oxide glass).
  
  The list is not exhaustive.
  
  | Properties | Soda–lime glass (for containers) | Borosilicate (low expansion, similar to Pyrex, Duran) | Glass wool (for thermal insulation) | Special optical glass (similar to Lead crystal) | Fused silica | Germania glass | Germanium selenide glass |
  | - | - | - | - | - | - | - | - |
  | Chemical composition, wt% | 74 $SiO_2,$ 13 $Na_2O,$ 10.5 CaO, 1.3 $Al_2O_3,$ 0.3 $K_2O,$ 0.2 $SO_3,$ 0.2 MgO, 0.01 $TiO_2,$ 0.04 $Fe_2O_3$ | 81 $SiO_2,$ 12.5 $B_2O_3,$ 4 $Na_2O,$ 2.2 $Al_2O_3,$ 0.02 CaO, 0.06 $K_2O$ | 63 $SiO_2,$ 16 $Na_2O,$ 8 CaO, 3.3 $B_2O_3,$ 5 $Al_2O_3,$ 3.5 MgO, 0.8 $K_2O,$ 0.3 $Fe_2O_3,$ 0.2 $SO_3$ | 41.2 $SiO_2,$ 34.1 PbO, 12.4 BaO, 6.3 ZnO, 3.0 $K_2O,$ 2.5 CaO, 0.35 $Sb_2O_3,$ 0.2 $As_2O_3$ | $SiO_2$ | $GeO_2$ | $GeSe_2$ |
  | Viscosity log(η, Pa·s) = A + B / (T in °C - $T_o)$ | 550–1450 °C: A = -2.309 B = 3922 $T_o$ = 291 | 550–1450 °C: A = -2.834 B = 6668 $T_o$ = 108 | 550–1400 °C: A = -2.323 B = 3232 $T_o$ = 318 | 500–690 °C: A = -35.59 B = 60930 $T_o$ = -741 | 1140–2320 °C: A = -7.766 B = 27913 $T_o$ = -271.7 | 515–1540 °C: A = -11.044 B = 30979 $T_o$ = −837 |
  | Glass transition temperature, $T_g,$ °C | 573 | 536 | 551 | ~540 | 1140 | 526 ± 27 | 395 |
  | Coefficient of thermal expansion, ppm/K, ~100–300 °C | 9 | 3.5 | 10 | 7 | 0.55 | 7.3 | |
  | Density at 20 °C, $[g/cm^3],$ x1000 to get $[kg/m^3]$ | 2.52 | 2.235 | 2.550 | 3.86 | 2.203 | 3.65 | 4.16 |
  | Refractive index $n_D$ at 20 °C | 1.518 | 1.473 | 1.531 | 1.650 | 1.459 | 1.608 | 1.7 |
  | Dispersion at 20 °C, $10^4×(n_F$ - $n_C)$ | 86.7 | 72.3 | 89.5 | 169 | 67.8 | 145 | |
  | Young's modulus at 20 °C, GPa | 72 | 65 | 75 | 67 | 72 | 43.3 | |
  | Shear modulus at 20 °C, GPa | 29.8 | 28.2 | | 26.8 | 31.3 | | |
  | Liquidus temperature, °C | 1040 | 1070 | | | 1715 | 1115 | |
  | Heat capacity at 20 °C, J/(mol·K) | 49 | 50 | 50 | 51 | 44 | 52 | |
  | Surface tension, at ~1300 °C, $mJ/m^2$ | 315 | 370 | 290 | | | | |
  | Chemical durability, Hydrolytic class, after ISO 719 | 3 | 1 | 3 | | | | |
  