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  • 1
    Electronic Resource
    Electronic Resource
    Dipole moments and Kerr constants of dibenzoates of some diols with different numbers of methylene units as model compounds for polyesters (1990)
    s.l. : American Chemical Society
    Macromolecules 23 (1990), S. 1139-1144 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma00206a036
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  • 2
    Electronic Resource
    Electronic Resource
    Identification of the short-range intramolecular excimers in polyacenaphthalene (1990)
    s.l. : American Chemical Society
    Macromolecules 23 (1990), S. 2560-2566 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma00211a025
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  • 3
    Electronic Resource
    Electronic Resource
    New method for quantitative functionalization of the terminus in poly(styrene). Naphthalene functionalization (1988)
    s.l. : American Chemical Society
    Macromolecules 21 (1988), S. 2294-2295 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma00185a072
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  • 4
    Electronic Resource
    Electronic Resource
    Measurements of electrical birefringence by using a transverse-field Pockels cell as a compensator (1988)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 59 (1988), S. 728-736 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An improved device for electrical birefringence measurements is described. The novel features of this apparatus include a new design of the Kerr cell and use of the Pockels cell as a compensator. These features show enhanced sensitivity and great improvement in reproducibility of results. A relationship between the intensity detected and the relative phase shifts in the Kerr and Pockels cells is determined by a matrix analysis of the amplitude of radiation passing through each optical element. Based on this analysis, a comparative study under different experimental configurations, as well as an evaluation of the effects of misalignments and methods to cancel the static birefringence, are made. From the results, the best experimental arrangement and procedure of measurement are deduced. Finally, the apparatus is checked by measuring Kerr constants (B) of several nearly isotropic solvents used for the study of polymers in solution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1139818
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  • 5
    Electronic Resource
    Electronic Resource
    Kerr constants of methyl benzoate and the dimethyl esters of phthalic, isophthalic, and terephthalic acids (1990)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 94 (1990), S. 8374-8378 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100384a071
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  • 6
    Electronic Resource
    Electronic Resource
    Kerr constant of poly (methyl phenyl siloxane) (1985)
    Springer
    Polymer bulletin 13 (1985), S. 263-270 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The molar Kerr constant at infinite dilution of atactic (Wm=0.5) poly (methyl phenyl siloxane) (PMPS) with ¯Mv=8 105, was determined from experimental measurements of electrical birefringence on its solutions in p-dioxane at 21±1 °C. The experimental result is 〈mK〉/x=(1.9±0.5) 10−25 m5V −2mol−1; the large estimated error of this result is due to the surprisingly low value of 〈mK〉/x of the PMPS. The theoretical value of this magnitude, calculated according to the RIS model is 〈mK〉/x=1.6 10−25 m5V −2mol−1 wich is in good agreement with the experimental result. Moreover, theoreticical analysis indicates that the reason for the low value of this magnitude, is that the dipole contribution to 〈mK〉/x is negative although not large enough to overcome the positive contribituion of polarizability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00254661
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  • 7
    Electronic Resource
    Electronic Resource
    Kerr constant of Dimethyl Terephthalate and Poly (Diethylene Glycol Terephthalate) (1984)
    Springer
    Polymer bulletin 11 (1984), S. 533-540 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Electrical, birefringence of Dimethyl Terephthalate (DMT) and Poly (Diethylene Glycol Terephthalate) (PDET) in p-dioxane solutions were measured at 20°C. The results were used to compute molar Kerr constants of both compounds at infinite dilution. The experimental results were 〈mK〉= = 780 and 〈mK〉= -732, both in units of 10−27m5V−2 mol−1, for DMT and PDET respectively. Theoretical analysis of 〈mK〉 of DMT indicates that the inductive effects that prevent the additivity of tensors of benzene and ester groups account for about 12% of the value of 〈mK〉. The tensor obtained for DMT was used, together with literature values of all the non optical parameters, to calculate 〈mK〉/x of PDET according to the RIS model. The concordance between theoretical and experimental results of this magnitude is excellent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01045333
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  • 8
    Electronic Resource
    Electronic Resource
    Molecular Mechanics Study of the Complexes of β-Cyclodextrin with 4-(dimethylamino)benzonitrile and Benzonitrile (1999)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 35 (1999), S. 467-485 
    Details
    ISSN: 1573-1111
    Keywords: Cyclodextrins ; inclusion complexes ; dimers ; molecular mechanics calculations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Molecular Mechanics calculations with the Tripos Force Field were employed to study the complexation of 4-(dimethylamino)benzonitrile (DMABN) and/or benzonitrile (BN) with β-cyclodextrin (βCD). The systems studied have 1 : 1 (DMABN : βCD and BN : βCD), 2 : 2 (DMABN : βCD) and 1 : 1 : 2 (DMABN : BN : βCD) stoichiometries. Evidence for the formation of such complexes, binding constants and other thermodynamic parameters were extracted from the analysis of the steady state fluorescence measurements performed in a previous work. The Molecular Mechanics study, based on the energy changes upon guest-host approaching, was performed in vacuo and in the presence of water as a solvent. Results show that the driving forces for 1 : 1 complexation are mainly dominated by non-bonded van der Waals host : guest interactions. However, the driving forces for association between 1 : 1 complexes to give 2 : 2 homo- or 1 : 1 : 2 heterodimers are dominated by non-bonded electrostatic interactions. Head-to-head electrostatic interactions between βCDs, which are presumably due to the hydrogen bonding formation between secondary hydroxyl groups of CDs, are responsible for most of the stability of the dimers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008018502072
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  • 9
    Electronic Resource
    Electronic Resource
    Intramolecular energy transfer in compounds with two 1-pyrenoate groups separated by methylene spacers (1996)
    Springer
    Journal of fluorescence 6 (1996), S. 41-50 
    Details
    ISSN: 1573-4994
    Keywords: Intramolecular energy transfer ; 1-pyrenoate ; methylene spacers ; fluorescence anisotropy ; fluorescence lifetime
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Steady-state fluorescence anisotropy (r) and fluorescence lifetime (τ) measurements have been used to study the efficiency of nonradiative singlet energy transfer as a function of alkane size in 1-pyrenecarboxylic acid alkanediyl esters (as a function ofm in Py-COO-(CH2) m -OOC-Py, where Py denotes pyrene substituted in the 1-position, andm=2–6). Experiments were performed in media of different viscosity, η, obtained by changing the temperature (from −20 to 40°C) of dilute solutions in ethylene glycol and by examination of the compounds in a solid matrix of poly(methyl methacrylate) (PMMA) at ambient temperature. The Py-COO-(CH2)m-OOC-Py exhibit intramolecular excimer emission in ethylene glycol at these temperatures, but the intensity of this emission is much lower than when these compounds are placed in common solvents of lower η. The values of τ indicate that excitation hopping or intramolecular energy transfer takes place between the chromophores attached to the ends of the alkane bridges. Values ofr obtained by the extrapolationsT/η→0 orτT/η→0 in ethylene glycol, as well as the values obtained in the rigid matrix of PMMA, show very little dependence onm. A theoretical conformational analysis, using the rotational isomeric state (RIS) model, was also performed. The combination of the experimental results forr in the media of high η with the theoretical (RIS) analysis produces an estimated value of 21 ±2 Å for the Förster radius in Py-COO-(CH2)m-OOC-Py.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00726725
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  • 10
    Electronic Resource
    Electronic Resource
    The ratio of excimer to monomer emission in diesters of 1-pyrenoic acid and five glycols (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 31 (1993), S. 213-220 
    Details
    ISSN: 0887-6266
    Keywords: excimer ; fluorescence ; Polyester ; rotational isomeric state theory ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The ratio of the intensities of excimer and monomer emission, ID/IM, has been measured for Py—COO—(CH2)m—OOC—Py (m = 2-6, Py = 1-pyrenyl) in solvents of different viscosity, η. These compounds are dimeric models for the corresponding polymers, selected to eliminate the influence of energy migration on the population of an excimer. The solvents are H(CH2)nOH, n = 1-7, and ethylene glycol. The values of ID/IM decrease as η increases, and the rate of this decrease is a function of m. Therefore the qualitative dependence of ID/IM on m is a function of η. In the limit as η → ∞, ID/IM is an odd-even function of m for m = 2-5, and the values at m = 5 and 6 are nearly identical. A rotational-isomeric state analysis of the conformations of the diesters can rationalize the appearance of the odd-even effect. This result is insensitive to assumptions about the extent of overlap of the two pyrene ring systems that is required for the production of emission in the excimer band. © 1993 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1993.090310210
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