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The groundstate-stable dimers in the non-crystalline regions of uniaxially drawn poly(ethylene terephthalate) (PET) films were used as chain-intrinsic fluorescent labels for studying the orientation distribution in the non-crystalline regions. As far as indicated by the spectra and the fluorescence decay law, the fluorescent group remains unchanged when the sample is uniaxially oriented by drawing above the glass transition temperature. In contrary to the behaviour of physically incorporated probe molecules, the orientation coefficient f of the dimers is proportional to the amorphous orientation coefficient f; concerning the fluorescence signal, 'amorphous' includes all the material outside the perfect crystal. During deformation, the orientation coefficient f follows approximately a superposition curve of crystallite-like orientation, separable in the initial range of stretching ratio λ <2.5, and of true-amorphous orientation of the affine network type that becomes noticably at λ>3. At temperatures closely above T, and within the selected range of stretching parameters, the fluorescence intensity of PET remains nearly constant with increasing stretching ratio λ; at λ>2.5, where the maximum crystallite orientation is achieved and the increase of amorphous orientation becomes noticably, a slight augmentation of the dimer concentration is observed. [ABSTRACT FROM AUTHOR]

Electrostriction of tactic polymethylmethacrylates in response to step-on and step-off dc-fields was investigated in the field strength range from 1 to 5 MV m at room temperature; one example of electrostriction under sinusoidal field is given. Three principal retardation time regions were found: τ=1.5 s, τ=30 s, and τ=140 s, each field strength independent. The retardation strengths belonging to these electrostrictive processes depend on tacticity. The low frequency limit of the electrostrictive volume compliance for the investigated PMMA is δ=−1.2×10 m V for atactic, δ=−2.3×10 m V for syndiotactic, and δ=−4.5 × 10 m V for isotactic PMMA. [ABSTRACT FROM AUTHOR]

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Copyright of Colloid & Polymer Science is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Colloid & Polymer Science is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Colloid & Polymer Science is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Colloid & Polymer Science is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Colloid & Polymer Science is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)