Polarizing Interference Microscope Research Articles

Refractive index and compressibility of Di64An36 glass over a pressure range of 0–5.0 GPa

Data on the refractive index, density, and bulk modulus variations of Di64An36 glass, which is used as a model basalt melt, were obtained with a polarization interference microscope and a high-pressure diamond anvil cell at ambient temperature and pressure up to 5.0 GPa. An anomalous decrease in the bulk modulus, Kt, was observed in the pressure range 0–1.0 GPa. The values of the zero-pressure isothermal bulk modulus, Kt,0 = 22.2, and variation of the bulk modulus with pressure, ΔKt/ΔP = 11.35, were derived using a linear equation relating Kt and P over the pressure range with the normal behavior of the compressibility. A comparison of our results with previous data on other glasses and melts showed that the bulk moduli of silicate glasses are similar to those of corresponding melts. The values of the pressure coefficient of the bulk moduli, ΔKt/ΔP, for glasses derived from linear equations are 2.5 times higher than the pressure derivative of the bulk modulus, K′T, derived using the Birch-Murnaghan equation for corresponding melts. The difference in ΔKt/ΔP and K′T has an effect on the compressibility of glasses and melts. The compressibility of glasses up to 5.0 GPa calculated as (d − d0)/d is almost two times lower than that of corresponding melts.

Study of some opto-mechanical parameters characterizing polypropylene suture fibers

The physical characteristic according to stretched and thermally treated polypropylene (PP) surgical suture fibers was studied interferometrically. Two-beam Pluta polarizing interference microscope connected to a mechanical device for study the draw ratios due to optical and thermally changes, at different temperatures (19–40°C). The resulting data of birefringence were utilized to calculate the average orientation functions, the form birefringence and the constants birefringence–strain relation and also the distribution of segments, bulk shear, Young's modulus, cohesive energy density and square of solubility parameter. The two types of polarization, the induced polarizability and the permanent dipole moment, were carried out for PP suture fibers. The present study demonstrates PP suture fibers structure using opto thermo-mechanical methods.

Refractive index and compressibility of the KAlSi3O8 glass at pressures up to 6.0 GPa

The refractive index of potassium aluminosilicate glass of the KAlSi3O8 composition in the pressure range up to 6.0 GPa has been measured using a polarizing interference microscope and an apparatus with diamond anvils. The changes in the relative density, which characterize the compressibility of the K2O · Al2O3 · 6SiO2 glass, have been estimated in the pressure range under investigation from the measured refractive indices within the framework of the theory of photoelasticity. The results have been compared with the data previously obtained for the Na2O · Al2O3 · 6SiO2 glass. Although the molar contents of Al2O3 and M2O (where M = K or Na) are identical in these glasses, the KAlSi3O8 glass exhibits a higher compressibility, which agrees with the lower degree of depolymerization of this glass as compared to that observed in the NaAlSi3O8 glass. The pressure derivative of the bulk modulus K′t, which is calculated from the Birch-Murnaghan equation for the KAlSi3O8 glass (K′t = 7–9), is higher than that for the NaAlSi3O8 glass (K′t= 5.5–6.0). An increase in the pressure derivative of the bulk modulus K′t upon replacement of the Na+ cations by the K+ cations is explained by the inhibition of compression of the large K+ cations, which are located in cavities and have a considerably larger orbital radius than the Na+ cations. This manifests itself in the fact that the curves describing the dependences of the change in the relative density (d − d0)/d (compressibility) on the pressure P for the KAlSi3O8 and NaAlSi3O8 glasses converge at pressures above 4.0 GPa.

Effect of pressure on the refractive index and relative density of the CaO·Al2O3·6SiO2 glass

The refractive index for glass of the CaO · Al2O3 · хSiO2 system with х = 6 in the range of pressures up to 6.0 GPa was measured using a polarization-interference microscope and an apparatus with diamond anvils. The changes in the relative density characterizing the compressibility of glass were estimated from the measured refractive indices within the framework of the theory of photoelasticity. The data were compared with the previous data for glasses of the same system with х = 2 and 4. The most compressible of the three glasses in the range 2.0–6.0 GPa was the CaO · Al2O3 · 6SiO2 glass. For glasses with х = 2, 4 and 6 we calculated the degrees of polymerization of silicon–aluminum–oxygen network, NBO/T (NBO – non-bridging oxygen), which are determined as the ratio of the number of gram-ions of non-bridging oxygen atoms to the total number of gram-ions of network formers. The structure–chemical parameter NBO/T was calculated with due regard for the formation of triclusters and highly coordinated aluminum. The degree of polymerization of the CaO · Al2O3 · хSiO2 glasses increases with increasing х, which agrees with the change of their relative density under pressure.

Determination of the optical and geometrical properties of fibres having skin–core structure

A method is suggested to determine both the refractive index and the transverse sectional shape and area of fibres, having skin–core structure, at the same time for the same region of the fibre. The method depends on using a fibre rotator device attached with Pluta polarizing interference microscope, to record the variation of the fibre thickness at each angle of rotation. Nylon 6 fibres having skin–core structure were used in this study. Beck-line method was used to determine the refractive index of the skin for light vibrating parallel and perpendicular to the fibre axis. To confirm the results of the suggested method, the optical microscope was used to determine the transverse sectional shapes of bundles of nylon 6 fibres. The mean refractive indices of the skin and core of nylon 6 fibres were determined. Microinterferograms are given for illustration.

Influence of pressure on the refractive index and relative density of glasses in the CaO-Al2O3-SiO2 system

The pressure dependences of the refractive index for aluminosilicate glasses of the compositions 0.167CaO · 0.167Al2O3 · 0.666SiO2 and 0.157CaO · 0.177Al2O3 · 0.666SiO2 at pressures up to 6.0 GPa are determined using a polarizing interference microscope and an apparatus with diamond anvils. The compressibilities of the glasses are calculated from the measured refractive indices within the framework of the theory of photoelasticity. The structural-chemical parameters NBO/T (where NBO is the number of gram-ions of nonbridging oxygen atoms and T is the total number of gram-ions of network formers) are calculated for the glasses under investigation with allowance made for the formation of triclusters and highly coordinated aluminum.

Geometrical and Optical Properties of Irregular Fibers as a Function of Draw Ratio

The Pluta polarizing interference microscope with a fiber rotator-mechanical device was used to detect the variation in the cross-sectional area, shapes and optical properties of irregular fibers during the cold drawing process. The rotation method was used to overcome the difficulty of measuring the transverse cross-sectional area of fibers with irregular shapes during their drawing process. Acrylic fibers of two denier were used during this investigation. Some optical parameters were measured, such as refractive indices and birefringence. The measurements of the refractive indices show that acrylic fibers have a negative birefringence. The polarizability-per-unit volume was used to clarify the negative birefringence of these fibers. Microinterferograms and the digitized images with their contour lines are given for illustration.

Interferometric detection of structure deformation due to cold drawing of polypropylene fibres at high draw ratios

A stress–strain device was attached to a two-beam polarizing interference microscope to investigate the structure deformation associated with fibre cold drawing. A polypropylene fibre was stretched at high draw ratios, D>6, and the interference patterns were automatically digitized and stored in computer storage media. The microinterferograms show that there are two different mechanisms that occur when the fibre is stretched, depending on whether with fast or slow drawing. In case of slow drawing, smooth deformation was detected, and in case of fast drawing, microcrack deformation was presented. The refractive indices and birefringence of the fibre were measured as a function of draw ratio. The refractive index profiles using fringe image analysis were calculated in cases of fast and slow drawing. The two-beam interferometric technique is a good technique to investigate and detect microcrack deformation across the diameter of a fibre. Microinterferograms are given for illustrations.

Degree of polymerization of the CaAl2Si2O8 aluminosilicate glass

The pressure dependence of the refractive index for a glass of the composition 0.50SiO2 · 0.25Al2O3 · 0.25CaO at pressures up to 5.0 GPa is determined using a polarizing interference microscope and an apparatus with diamond anvils. The densities and compressibilities of the glass are calculated from the measured refractive indices within the framework of the theory of photoelasticity. The results are compared with the data obtained earlier for vitreous silica. The lower compressibility of the glass under investigation as compared to the compressibility of fused silica is in agreement with the degree of polymerization that is calculated with due regard for the formation of triclusters from the relationship NBO/T = (2O + 3Ot − 4T)/T, where NBO (nonbridging oxygen) is the number of nonbridging oxygen atoms; O is the number of gram-ions of oxygen, except for of tricluster oxygen; Ot is the number of gram-ions of tricluster oxygen; and T is the total number of gram-ions of network formers.

Interferometric Determination of Structural Properties of PEN Highly Oriented Fiber

Some optical and structural properties of Poly(ethylene naphthalate-2.6-dicarboxylate), PEN, highly oriented fiber was determined using an automatic variable wavelength interferometric, VAWI, technique. This technique is commonly used jointly with the double refracting polarizing interference microscope designed by Pluta. The microscope was used in two different positions, the subtractive position for determining the spectral dispersion curves of the birefringence and the crossed position for determining the spectral dispersion curves of the refractive indices. The resulting data are utilized to calculate some dispersion and structural parameters such as Cauchy's constants, natural wavelength, dispersion energy, oscillation energy, polarizability per unit volume, dielectric constant, dielectric susceptibility, optical orientation function, and the orientation angle. Microinterferograms are given for illustration.

The role of iodine treatment in enhancing the optical and structural properties of stretched nylon 6 fibres

Stretched nylon 6 fibres are treated with iodine at 50 °C at different time intervals. The effects of the treatment on the optical and structural parameters are investigated. Using the double-beam Pluta polarizing interference microscope, the interference patterns are recorded for the investigated samples and used for calculating the refractive indices, birefringence and other optical properties. The refractive indices and the birefringence values are directly proportional to the time of iodine evaporation. The iodine treatment increases the isotropic refractive index, mean polarizability per unit volume, surface reflectivity and orientation function, while decreasing the orientation angle (θ). The angle (θm) between the chain axis and the dipole moment seems to be constant. The investigated parameters show remarkable variation for the uniaxially drawn fibres to draw ratios (3 and 3.5). Moreover, the iodinated undrawn and drawn samples reveal an increase in the magnitude of the investigated parameters compared with those only annealed at the same conditions of temperature and time. The obtained results indicate that the iodine treatment modifies the nylon 6 fibre structure and consequently the optical properties, which may be useful for different industrial purposes.

Influence of Drawing and Temperature on the Optical and Structural Properties of Monofilament PP Sutures

Abstract The influence of drawing and temperature on the optical and structural properties of monofilament polypropylene sutures (PP) were investigated using interferometry. Two techniques have been used in this study: 1) the polarizing interference microscope, 2) multiple-beam Fizeau interferometry. The polarizing interference microscope is used to study the variation of refractive indices and birefringence of PP sutures at different draw ratios and stresses. The stress-strain diagram of PP sutures was studied. The resulting data was used to calculate the average work per chain, Poisson's ratio, strain optical coefficient, Young's modulus and optical orientation function. Multiple-beam Fizeau interferometry was used to study the temperature effect on optical properties of PP sutures with temperature ranging from 19 to 40°C. Relationships between the optical parameters at different temperatures are given. Calculation of the density, crystallinity, dielectric constant and dielectric susceptibility at different temperatures are done. The results obtained, clarify the effect of drawing and temperature on the structure of PP sutures. Microinterferograms are given for illustration.

Interferometric characterization and analysis of silver-exchanged glass waveguides buried by electromigration: slab, channel and slab-sided channel configurations

Channel and slab waveguides were fabricated by thermal Ag+/Na+ exchange in glass and buried by field-assisted diffusion. The mask was fabricated in a two-step photolithographic process by means of low-cost optics. A procedure to thinly and accurately slice samples with standard cutting and polishing machines is demonstrated. The two-dimensional index distribution of the sample slice was measured by a commercial polarizing interference microscope using a light-emitting diode as light source. The index profiles are analysed by taking into account the electromigration dynamics. The main finding is that the index peak of a channel waveguide close to a slab waveguide (slab-sided channel waveguide) was found to be deeper than that of a similar isolated channel waveguide. A preliminary application is proposed to improve the coupling efficiency between the channel and slab buried waveguides used in some integrated optical devices made in glass, such as arrayed waveguide gratings.

Effect of temperature on the dispersion properties of polypropylene fibers

AbstractA Biolar PI polarizing interference microscope (a Pluta microscope) attached to a special hot stage was used to study the influence of temperature on the dispersion properties of polypropylene fibers with different deniers (6 D and 90 mm, 6 D and 150 mm, and 12 D and 150 mm) over the temperature range of 30–50°C. This study was carried out with a variable‐wavelength interferometry technique. Constant A of Cauchy's dispersion formula and the oscillation and dispersion energies for light vibrating parallel and perpendicularly to the fiber axis were determined at different temperatures. Microinterferograms are given for illustration. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1135–1141, 2005

Interferometric determination of the refractive indices and birefringence of some highly oriented fibres

Variable wavelength interferometric technique (VAWI) is a direct method for determining the refractive indices and birefringence of highly oriented fibres. This method uses the polarizing interference Pluta microscope with a monochromatic light from wedge interference filter that provides a continuously variable wavelength. The standard calibration process of the Pluta polarizing interference microscope is carried out and a calibration graph is obtained. The refractive indices and birefringence of PEN, CONEX and TECHNORA were measured over the visible range of the spectrum and the constants for the Cauchy's dispersion formula were determined. The oscillation and dispersion energies were calculated from the measurements of the refractive index.

Effect of high pressure on the refractive index and density of natural aluminosilicate glasses of alkali basalt composition in the SiO2-Al2O3-TiO2-Fe2O3-P2O5-FeO-MnO-CaO-MgO-Na2O-K2O system

The pressure dependence of the refractive index for a natural glass of composition 0.528SiO2 · 0.019TiO2 · 0.102Al2O3 · 0.021Fe2O3 · 0.062FeO · 0.002MnO · 0.081CaO · 0.072MgO · 0.068Na2O · 0.034K2O · 0.011P2O5 at pressures up to 5.0 GPa is determined using a polarizing interference microscope and an apparatus with diamond anvils. The densities and compressibilities of the glass are calculated from the measured refractive indices within the theory of photoelasticity. The results are compared with the data obtained earlier for another glass that has a similar composition but contains a lower concentration of alkali metal oxides. A higher compressibility of the glass under investigation as compared to the compressibility of the glass studied previously is in agreement with the degrees of polymerization that are calculated taking into account the formation of triclusters.

Detection of the variation of the optical and geometrical parameters of fibres due to the cold drawing process

A method is described to detect the variation of the refractive index profile, transverse sectional shapes, areas and mechanical properties of fibres during the cold drawing process. A rotator-mechanical drawing device is used for rotating the fibre around its longitudinal axis during the cold drawing process for the fibre from the two fixed ends. In this method, the rotator-mechanical drawing device is attached with a Pluta polarizing interference microscope for detecting the variation of the geometrical dimensions of fibres in front of the interferometer. The suggested method permits determining the refractive index profile of the drawn fibres taking into consideration the transverse sectional area and the enclosed area under the fringe shift. Nylon 6 and polypropylene fibres are used in this investigation. The optical orientation factor and orientation angle are calculated for these fibres to clarify the orientation of molecules due to the cold drawing process. Microinterferograms are given for illustration.

Determination of radial structural properties and spectral dispersion curves of poly(aryl ether ether ketone) fibre

AbstractPoly(aryl ether ether ketone) (PEEK) fibre was studied using a variable wavelength interferometric technique (VAWI). This technique was used in conjunction with a Pluta polarizing interference microscope to determine the spectral dispersion curves of fibre refractive indices and birefringence fibre. The results were used to calculate the dispersion properties of the fibre, ie dispersion and oscillation energies, Cauchy's constants of dispersion relation and the natural wavelength of the fibre. The radial refractive index and birefringence profiles were also determined, taking into consideration the refraction of light beam by the fibre, and some radial structural profiles were then calculated using a ring‐zonal model. The measurements of these radial profiles are required for optimizing the spinning and processing of manufactured textile fibres. The Fraunhofer diffraction pattern of a He–Ne laser beam was used to determine the average thickness of the fibre. Microinterferograms are presented for illustration. Copyright © 2003 Society of Chemical Industry

The effects of L- and D-stereoisomers on the transmitter secretion and ionic currents in the motor nerve ending.

In this work, we studied the effect of L - and D -stereoisomers of arginine on ionic currents in the motor nerve ending and induced transmitter secretion in the neuromuscular synapse of the frog. The experiments were performed with the neuromuscular junction of cutaneous pectoris muscle of the marsh frog in autumn and winter. The preparations were constantly perfused with the Ringer solution for poikilothermal animals. To eliminate the action potentials and contractions of muscular fibers, we used the Ringer solution with a decreased Ca 2+ concentration, containing 118 mM NaCl, 2.5 mM KCl, 0.3‐0.4 mM CaCl 2 , 2.0‐4.0 mM MgCl 2 , and 2.4 mM NaHCO 3 (pH 7.4‐7.6 at 20ie ). For extracellular lead of synaptic signals, we used glass microelectrodes that were applied on the proximal part of the nerve ending (30 to 50 μ m from the last myelinated axonal segment). This process was controlled visually, using a polarizationinterference microscope (resolution, 400 〈 ). The motor nerve was stimulated by rectangle electric pulses with overthreshold amplitude (duration, 0.3‐0.4 ms; frequency, 0.5‐1 pps). We recorded the three-phase response (+ ‐ +) of nerve ending to each stimulus, which reflected the ionic currents forming the action potential, and the subsequent endplate current (EC) [2]. The first positive phase is a passive (capacitive) current, generated by the entering action potential; the second, negative phase is an entering sodium current; and the third positive phase is an outgoing potassium current across voltage-dependent and Calcium-activated potassium channels [2]. Because our experiments were performed at low extracellular concentration of Ca 2+ , it can be accepted that Calcium-activated potassium current predominantly reflects the voltage-dependent potassium current. The analysis, averaging, and accumulation of recorded signals were performed using a Pentium II PC. We determined the amplitude and duration of each phase of nerve-ending response relative the baseline value and the EC amplitude. The quantum content of EC ( m ) was determined by counting the zero responses according to the equation: m = , where

Optomechanical variations in cold‐drawn thermally treated polypropylene fibers

AbstractA two‐beam polarizing interference microscope with a microstrain device was used for measuring some optical and mechanical parameters for polypropylene (PP) fibers at room temperature (28 ± 1°C). The changes in the molecular orientation were evaluated to obtain orientation factors f2(θ), f4(θ), f6(θ), 〈P2(cos θ)〉, 〈P4(cos θ)〉, and crystalline and amorphous orientation functions Fc and Fa, respectively. The shrinkage factor, uniaxial tension, true stress, molar refractivity R, surface reflectivity R′, the crosslink density Ns, the chain entanglement density Nc, the segment anisotropy γs, and the number of chains N′ were calculated. In addition, the shrinkage stress was found to increase with the increase of draw ratio. The dielectric constant ε, the dielectric susceptibility η, the average work per chain w′, and the constants of the stress–birefringence equation were obtained. Comparison between Hermans's optical orientation functions and the corrected formulas by de Vries are given. The values of fully oriented refractive indices n1 and n2 were found. The generalized Lorentz–Lorenz equation given by de Vries was used to determine the structural parameters of PP fibers. An empirical formula was suggested to correlate the changes in the evaluated parameters with different draw ratios, and its constants were determined. The study demonstrated changes on the molecular orientation factors and evaluated microstructural parameters as a result of an applied cold‐drawing process. Relationships between the calculated parameters and the draw ratios, together with microinterferograms were presented for illustration. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 729–738, 2003