1 Introduction
2 Fiber design
Oxide composition | SF6 | NC21 |
---|---|---|
\({SiO}_{{2}}\)
| 27.7 | 55.0 |
\({As}_{{2}}{O}_{{3}}\)
| 0.3 | - |
PbO | 70.5 | - |
\({Na}_{{2}}{O}\)
| 0.5 | 9.5 |
\({K}_{{2}}{O}\)
| 1.0 | 5.5 |
\({B}_{{2}}{O}_{{3}}\)
| - | 26.0 |
\({Al}_{{2}}{O}_{{3}}\)
| - | 1.0 |
\({Li}_{{2}}{O}\)
| - | 3.0 |
Thermo-physical properties | SF6 | NC21 |
---|---|---|
Refractive index \({{\varvec{n}}}_{D}\)
| 1.805 | 1.518 |
Linear thermal expansion coefficient for the range \(20 \div 300^{\circ }\hbox {C}~{{\varvec{\upalpha }}}~[10^{-7}\,\hbox {K}^{-1}]\)
| 87.9 | 82.0 |
Lower annealing temperature \({t}_{{d}}~[^{\circ }\hbox {C}]~\hbox {log} \upeta =14.6\)
| 405.2 | 462 |
Transformation temperature \({T}_{{g}}~[^{\circ }\hbox {C}]~\hbox {log}\upeta =13.4\)
| 441.8 | 487 |
Upper annealing temperature \({t}_{{g}}~[^{\circ }\hbox {C}]~\hbox {log}\upeta =13.0\)
| 449.7 | 496 |
Dilatometric softening point DSP \([^{\circ }\hbox {C}]\hbox { log}\upeta =11.0\)
| 463.2 | 527 |
Characteristic glass temperatures related to dynamic viscosities \(\upeta \) (\(\upeta \) given in Poises) \([^{\circ }\hbox {C}]\)
| ||
\(\hbox {log} \upeta =9.0\)
| 520 | 580 |
\(\hbox {log} \upeta =6.0\)
| 600 | 670 |
\(\hbox {log} \upeta = 4.0\)
| 665 | 740 |
\(\hbox {log} \upeta =2.0\)
| 880 | 860 |