Light depolarization microscopy

LDM light depolarization microscopy Mylar polyethylene glycol... 

The overall crystallization rate is used to follow the course of solidification of iPP. Differential scanning calorimetry (DSC), dilatometry, dynamic X-ray diffraction and light depolarization microscopy are then the most useful methods. The overall crystallization rate depends on the nucleation rate, 1(0 and the growth rate of spherulites, G(0. The probabilistic approach to the description of spherulite patterns provides a convenient tool for the description of the conversion of melt to spherulites. The conversion of melt to spherulites in the most general case of nonisothermal crystallization is described by the Avrami equation ... 

One of the key experimental results leading to the elucidation of this overall structural puzzle involved depolarized reflected light microscopy (DRLM) studies on NOBOW freely suspended films in the high-temperature SmCP phase.48 In the freely suspended films it appears that only one phase is observed, which is assumed to be the phase forming the majority domains in the EO cells. The DRLM experiment provides two key results. First, thin films of any layer number have a uniformly tilted optic axis, suggesting all of the layer interfaces are synclinic. Second, films of even-layer number are nonpolar, while films of odd-layer number are polar, with the polar axis oriented normal to the plane of the director tilt (lateral polarization). 

Homo-FRET is a useful tool to study the interactions in living cells that can be detected by the decrease in anisotropy [106, 107]. Since commonly the donor and acceptor dipoles are not perfectly aligned in space, the energy transfer results in depolarization of acceptor emission. Imaging in polarized light can be provided both in confocal and time-resolved microscopies. However, a decrease of steady-state anisotropy can be observed not only due to homo-FRET, but also due to rotation of the fluorescence emitter. The only possibility of discriminating them in an unknown system is to use the variation of excitation wavelength and apply the... 

Figure 4.1. Time scales for rotational motions of long DNAs that contribute to the relaxation of the optical anisotropy r(t). Experimental methods used to study these motions in different time ranges are also indicated along with the authors and dates of some early work in each case. FPA, Fluorescence polarization anisotropy (Refs. 15, 18-20, and 87) TPD, transient photodichroism (Refs. 28 and 62) TEB, transient electric birefringence (Refs. 26 and 27) DDLS, depolarized dynamic light scattering (Ref. 116) TED, transient electric dichroism (Refs. 25, 115, and 130) Microscopy, time-resolved fluorescent microscopy (Ref. 176).

A more quantified approach to microscopy involves measuring the depolarized light intensity with a photocell, and plotting this quantity as a function of temperature. This approach is particularly useful in determining the clearing transition when rather broad transitions, quite usual for polymers, are obtained Unless care is taken to ensure a constant field of view and constant sample thickness, this method should be considered to be only semiquantitative as a measure of depolarized light intensity. 

Depolarized Light Intensity and Photometric Thermal Microscopy... 

The technique of depolarized light intensity (DLI) microscopy was introduced by Magill (80) in 1960. Basic elements of the apparatus were a light source, polarizers, a sample holder, an analyzer, and a suitable recording system. Barrall and Johnson (74) and Miller (75, 76) have described applications of this technique to polymeric samples. Miller (75) prefers to call this technique thermal polarization analysis (TPA). 

DDLS depolarized dynamic light scattering FEG-SEM field emission gun scanning electron microscopy SANS small angle neutron scattering... 

Depolarized light microscopy, DLM, can be used to measure light intensity (7) as a function of time ( ) and... 

Structure development has been followed by numerous experimental techniques, many authors often combining several of them rheological measurements, optical microscopy, optical measurements (birefringence, dichroism, turbidity, depolarized light intensity [DLI]), SALS, SAXS, WAXD, and so on. These techniques have been used ... 

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