Radial distribution of the refractive index in light-focusing rods: determination using Interphako interference microscopy

1977 ◽  
Vol 16 (4) ◽  
pp. 1050 ◽  
Author(s):  
Yasuji Ohtsuka ◽  
Yutaka Shimizu
2011 ◽  
Vol 19 (24) ◽  
pp. 24061 ◽  
Author(s):  
Hein L. Leertouwer ◽  
Bodo D. Wilts ◽  
Doekele G. Stavenga

A ray-tracing analysis for calculating, by means of interference microscope data, the radial distribution of refractive index, n ( r ), for fibres of round cross section has been formulated, solved, tested and used to determine n ( r ) for high-speed direct-spun polyethylene terephthalate (PET) fibres. The formulation was based on work by Kahl & Mylin (1965) originally performed to explore the radial density profiles in cylindrically symmetrical explosions. The equations were formulated with proper boundary conditions at the fibre surface, correcting a fundamental error that has caused problems for 20 years. This correct boundary condition unfortunately made it impossible to invert, as had been done in all previous work, the resulting integral equations, which consequently were solved by a nonlinear least-squares approximation. The analysis corrected a serious problem noted in the literature: namely, that the refractive index profile obtained for a particular fibre depended on the refractive index of the immersion liquid used to make the measurement. Refractive index profiles observed for PET fibres produced by high-speed direct spinning had concave-down curvature, the opposite of expectations based on previous work. This initial result suggests that when direct-spun, under crystallizing conditions, PET fibres develop a mainly radial density or quench profile, whereas fibres spun under conditions that give little crystallinity have a mainly radial orientation gradient. Experiments to test this suggestion further have not been done yet.


1983 ◽  
Author(s):  
Antonov I. P. ◽  
Goroshkov A. V. ◽  
Kalyunov V. N. ◽  
Markhvida I. V. ◽  
Rubanov A. S. ◽  
...  

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Kyoung Hou Kim ◽  
Yang Hun Lee ◽  
Hyun Hok Cho ◽  
Takeshi Kikutani

AbstractThe physical properties of poly(trimethylene terephthalate) (PTT) fibres were improved by means of vibration in the hot-drawing and annealing, which may be caused by the developed molecular packing. For high-speed spun PTT fibers, it was not until at the take-up speed of 3~4 km/min that the orientation induced crystallization started to emerge due to extensional stress occurred in spin line; confirmed from the results of WAXD and DSC. The PTT fibers obtained at the take-up speeds of 2~3 km/min and then drawn and annealed with vibration possessed low density and weight-crystallinity, but their birefringence was especially high. Moreover, the estimation of both refractive index parallel and normal directions to fiber axis using the interference microscopy showed that the refractive index parallel to the fiber axis was very high, which enhanced the mechanical properties of PTT fiber. Accordingly, the well-oriented chains along the fiber axis allow the PTT fiber to have better physical property such as elastic recovery although the PTT fiber has low density and crystallinity compared to PET and PBT. In effect, the PTT fiber possesses lower birefringence of over 10 times than those of PET and PBT due to its chain conformational characteristics. Therefore, we do suggest that the structural assessment against the subsequent mechanical properties according to various processes in the PTT fiber is preferred to be estimated through the respective refractive indices of parallel and normal to the fiber axis rather than conventional methods such as birefringence, crystallinity, and crystalline orientation.


2011 ◽  
Vol 244 (3) ◽  
pp. 223-229 ◽  
Author(s):  
A. I. YUSIPOVICH ◽  
M. V. ZAGUBIZHENKO ◽  
G. G. LEVIN ◽  
A. PLATONOVA ◽  
E. Y. PARSHINA ◽  
...  

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