Thermooptical analysis

PMCS-4 with different ratios of trans- and cis-sequences in the backbone possess one and the same glass transition temperature, and the crystallinity degree is lower that for PDMS. While polymeric chain is enriched by trans-units, crystallinity increases [27], By methods of DSC, X-ray diffraction and thermooptical analysis, it have been detected that besides glass transition (Tg) and melting (Tmeit), polymers synthesized from monomers containing up to 95 - 100% of tram-isomers display a phase transition in the temperature range of 70 - 90°C, which is simulated as a transition from meso-morphous to isotropic state (Figure 2). 

TOA, thermooptical analysis DSC, differential scanning calorimetry TMDSC, temperature-modulated DSC Real, reaction calorimetry DTA, differential thermal analysis XRPD, X-ray powder diffraction TG, thermogravimetry. 

It is thus clear that in addition to the sample absorbance and excitation laser power, the thermal lens signal is directly proportional to dn/dT and inversely proportional to the k value of the solvent. Nonpolar, volative organic solvents such as benzene, carbon tetrachloride and hexane, should provide good media for thermal lens measurements owing to their high dn/dT and low k values. Conversely, water, which is the most powerful and widely used solvent in spectrochemical analysis is considered to be the worst mediiun for thermooptical techniques because it has very low dn/dT... 

Thermooptical detection has been combined with CE and used for protein and peptide Edman degradation sequencing detection, native protein detection, as well as the analysis of derivatized amino acid mixtures. " Frequency-doubled argon-ion lasers have been employed to supply an UV (257 nm) pump beam for the analysis of dansylated amino acids as well as the analysis of etopside and etopside phosphate in human blood plasma. In addition, two-color thermooptical absorbance detectors have been constructed, where each laser serves a dual role of pump and probe this system can be used to detect analytes that absorb in differing regions of the electromagnetic spectrum. 

Apart from the simultaneous coupled thermoana-lytical techniques (TG-DSC and TG-DTA), residue analysis appears to have attracted fewer experimentalists than evolved gas analysis. Nevertheless, the ability to observe a sample by thermooptical methods, such as DSC-thermomicroscopy (or optical DSC), DTA-photometry or video microscopy imaging-TG (VMI-TG), as it is heated under conditions of controlled atmosphere and heating rate, provides a valuable supplement to thermal analysis techniques. In fact, DSC is non-specific and cannot distinguish between a phase change and a fusion reaction. Using thermomicroscopic methods... 

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