REGULARITIES OF FORMATION OF SYNTHETIC OPTICAL ANISOTROPY OF POLYMETHYL METHACRYLATE FOR POLARIMETRIC APPLICATION

2020 ◽  
Vol 55 ◽  
pp. 173-178
Author(s):  
A.V. Samoylov ◽  

General principles of wav plate manufacturing are considered. The possibility of the formation of synthetic optical anisotropy of polymethyl methacrylate (PMMA) by the method of its uniaxial stretching is investigated. The most promising is a method for manufacturing waveplates, which includes the stage of controlled stretching of the polymer material to the required phase shift value, which would generally exclude the stage of machining the plates. The general orderliness of the molecules in the polymer resulting from stretching (orientation) leads to the oriented state of the polymer, and, consequently, to the general anisotropy of the physical and optical properties. In this state, a clearly pronounced uniaxial orientation of polymer chains is observed. As a result, chain macromolecules, randomly (statistically) oriented in the initial PMMA, acquire orientation under the influence of an external directed tensile force. The anisotropy of the optical properties of uniaxially stretched PMMA is manifested in the fact that it has different refractive indices for light polarized parallel to the direction of stretching (orientation) and in the perpendicular direction (birefringence). The regularities of the formation of the synthetic optical anisotropy of PMMA have been studied. The dependences of the birefringence values of uniaxially stretched PMMA on the initial sheet thickness, stretching temperature, and degree of stretching have been measured. It has been shown that the value of birefringence is directly proportional to the thickness of the initial sheet and the degree of stretching and inversely proportional to the stretching temperature. The spectral dependence of the birefringence value is measured. Achromatic and superachromatic waveplates were made from uniaxially stretched PMMA. The spectral characteristics of the phase shift of the manufactured waveplates are given. The availability of the starting material, the technological simplicity of the formation of the initial components for waveplates, as well as the possibility of manufacturing waveplates of large dimensions and high quality, make polymethyl methacrylate with artificially induced anisotropy a promising material for the manufacture of achromatic and superachromatic waveplates.

Nanoscale ◽  
2021 ◽  
Author(s):  
Yiduo Wang ◽  
Yingwei Wang ◽  
Yulan Dong ◽  
Li Zhou ◽  
Hao Wei ◽  
...  

To date, outstanding linear and nonlinear optical properties of tellurene, caused by multiple two-dimensional (2D) phases and optical anisotropy, have been attracted considerable interest for potential nanophotonics applications. In this...


2014 ◽  
Vol 22 (3) ◽  
Author(s):  
J. Kędzierski ◽  
K. Garbat ◽  
Z. Raszewski ◽  
M. Kojdecki ◽  
K. Kowiorski ◽  
...  

AbstractOptical properties of a nematic liquid crystal with small refractive index and small birefringence were studied. The ordinary and extraordinary refractive indices and birefringence were measured as functions of temperature by using an Abbe refractometer and wedge nematic cells. From values of these indices the nematic orientational order parameter was calculated by using several methods and corresponding mathematical models. Kuczyński et al. method was found to be suitable for determining the order parameter also for materials featuring small ordinary refractive index, with unknown density.


Polymer ◽  
2005 ◽  
Vol 46 (11) ◽  
pp. 3927-3935 ◽  
Author(s):  
Andreas Schoene ◽  
Andrzej Ziabicki ◽  
Leszek Jarecki

2011 ◽  
Vol 221 ◽  
pp. 289-294 ◽  
Author(s):  
Guo Hong Zhang ◽  
Jian Hui Qiu ◽  
Liang Shao ◽  
Xie Fu

Based on the novel USW method, the welds of Polylactide (PLA) - Polyformaldehyde (POM) and PLA - polymethyl methacrylate (PMMA) have been carried out. The interdiffusion processes of polymer chains have also been investigated according to the reptation theory and the hauling theory. The welding strengths are carried out by the universal tester and the rupture interfaces are observed using the scanning electron microscope. The best welding strength is 52MPa (90% compared with PLA of the PLA-POM system), which can reach the tensile strength of IPS. The molecules of POM are much easier to inter-diffuse than those of PLA and PMMA.


1993 ◽  
Vol 323 ◽  
Author(s):  
David C. Rich ◽  
Peggy Cebe ◽  
Anne K. St. Clair

AbstractControl of the refractive index in low dielectric constant polyimides through modification of chemistry and structure was investigated. The optical refractive indices of several low dielectric constant polyimides were measured, and the effects of orientation on optical anisotropy were determined. Refractive index in these polyimides was found to decrease with increasing fluorine content due primarily to the low electronic polarizability of the fluorine-carbon bonds. In zone drawn polyimides, refractive index was found to increase substantially in the direction of the draw, but decrease substantially normal to the draw direction. This was explained in terms of the preferential alignment of the polymer chains.


Author(s):  
Борис Магометович Хуболов

В работе измерены спектральные зависимости оптической плотности аморфных тонких пленок оксидной натрий-вольфрамовой бронзы тетрагональной структуры состава NaWO, конденсированной на стеклянные подложки, термостатированные при температурах 373,473 и 573 K, а так же отожженные на воздухе и в вакууме, и электрохромно окрашенных. В качестве исследуемой оптической характеристики была выбрана оптическая плотность D, пропорциональная, как известно, коэффициенту поглощения. Спектральные измерения пленок, осажденных на подложки в диапазоне температур 373,473 и 573 K показали однотипность спектральных характеристик, с пиком экситонного поглощения в ближнем ультрафиолете. Полоса минимального поглощения лежит в диапазоне длин волн 400÷460 нм, а примесного поглощения - широкой полосой в области 650 ÷1000 нм с максимумом в диапазоне 900÷1000 нм. Подобная спектральная характеристика и определяет сине-голубой цвет тонкой пленки на просвет. Изучение оптических свойств тонких пленок натрий-вольфрамовых бронз представляет собой актуальную задачу. The spectral dependences were measured of the optical density of amorphous thin films of sodium-tungsten oxide bronze of the tetragonal structure and the composition NaWO, condensed on glass substrates, thermostated at temperatures of 373, 473 and 573 K, as well as annealed in air vacuum, and electrochromically colored. The optical density D, which is proportional, as is known, to the absorption coefficient, was chosen as the studied optical characteristic. Spectral measurements of films deposited on substrates in the temperature range of 373, 473 and 573 K showed the same type of spectral characteristics, with a peak of the exciton absorption in the near ultraviolet. The band of minimum absorption lies in the wavelength range of 400÷460 nm, while that of the impurity absorption is a wide band in the region of 650÷1000 nm with a maximum in the range of 900÷1000 nm. This spectral characteristic determines the blue-blue color of a thin film in transmission. The study of the optical properties of thin films of sodium-tungsten bronzes is an urgent problem.


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