Chromophore-functionalized glassy polymers with large second-order nonlinear optical responses. Transient dynamics and local microstructure of poly(p-hydroxystyrenes) as assessed by in-situ second harmonic generation techniques

Millicent A. Firestone, Mark A Ratner, Tobin J Marks, Weiping Lin, George K. Wong

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Microstructural relaxation of thin films of the poled, chromophore-functionalized amorphous polymer N-(4-nitrophenyl)-(S)-prolinoxypoly(p-hydroxystyrene) has been studied by in-situ second harmonic generation (SHG) techniques. The temporal and temperature dependence of the SHG intensity decay has been analyzed as a function of poling and processing parameters within the framework of the Kohlrausch-Williams-Watts (KWW "stretched exponential") model. The average SHG relaxation time, τ, increases rapidly upon reduction of the applied poling field strength, with increasing poling time (physical aging), and with decreasing film temperature. The other KWW parameter, β, which reflects the distribution of relaxation times, decreases (the distribution broadens) moderately with increases in the applied electric field strength and strongly with increases in poling time (physical aging). The observed value of β increases (the distribution narrows) with increasing film temperature. These trends and the variation in KWW parameters yield information regarding reorientation dynamics of the tethered chromophore molecules within the polymer matrix and thus on the nature of the system subspace which is explored during relaxation. Both parameters reveal a strikingly narrower distribution of relaxation times/reduced rotational mobility versus chromophore-doped, "guest-host" systems and classify the present materials as Angell "intermediate" glasses. The temperature dependence of the second harmonic signal decay after poling field cessation can be divided into two distinct regions: (i) above Tg, where the dynamics are characteristically nonlinear and best described by the Williams-Landel-Ferry (WLF) equation; (ii) below Tg, where the behavior is linear and modeled adequately by the Arrhenius equation. Analysis of the growth of the second harmonic signal as the poling field is applied yields a similar picture; however, limiting SHG values at temperatures significantly above Tg appear to be influenced by both thermal disruption of chromophore alignment and ion conduction/space charge effects.

Original languageEnglish
Pages (from-to)2260-2269
Number of pages10
JournalMacromolecules
Volume28
Issue number7
Publication statusPublished - 1995

Fingerprint

Chromophores
Harmonic generation
Polymers
Microstructure
Relaxation time
Temperature
Aging of materials
Polymer matrix
Electric space charge
Electric fields
Ions
Glass
Thin films
Molecules
Processing

ASJC Scopus subject areas

  • Materials Chemistry

Cite this

@article{1de3c074a72644feba650e758ef091d6,
title = "Chromophore-functionalized glassy polymers with large second-order nonlinear optical responses. Transient dynamics and local microstructure of poly(p-hydroxystyrenes) as assessed by in-situ second harmonic generation techniques",
abstract = "Microstructural relaxation of thin films of the poled, chromophore-functionalized amorphous polymer N-(4-nitrophenyl)-(S)-prolinoxypoly(p-hydroxystyrene) has been studied by in-situ second harmonic generation (SHG) techniques. The temporal and temperature dependence of the SHG intensity decay has been analyzed as a function of poling and processing parameters within the framework of the Kohlrausch-Williams-Watts (KWW {"}stretched exponential{"}) model. The average SHG relaxation time, τ, increases rapidly upon reduction of the applied poling field strength, with increasing poling time (physical aging), and with decreasing film temperature. The other KWW parameter, β, which reflects the distribution of relaxation times, decreases (the distribution broadens) moderately with increases in the applied electric field strength and strongly with increases in poling time (physical aging). The observed value of β increases (the distribution narrows) with increasing film temperature. These trends and the variation in KWW parameters yield information regarding reorientation dynamics of the tethered chromophore molecules within the polymer matrix and thus on the nature of the system subspace which is explored during relaxation. Both parameters reveal a strikingly narrower distribution of relaxation times/reduced rotational mobility versus chromophore-doped, {"}guest-host{"} systems and classify the present materials as Angell {"}intermediate{"} glasses. The temperature dependence of the second harmonic signal decay after poling field cessation can be divided into two distinct regions: (i) above Tg, where the dynamics are characteristically nonlinear and best described by the Williams-Landel-Ferry (WLF) equation; (ii) below Tg, where the behavior is linear and modeled adequately by the Arrhenius equation. Analysis of the growth of the second harmonic signal as the poling field is applied yields a similar picture; however, limiting SHG values at temperatures significantly above Tg appear to be influenced by both thermal disruption of chromophore alignment and ion conduction/space charge effects.",
author = "Firestone, {Millicent A.} and Ratner, {Mark A} and Marks, {Tobin J} and Weiping Lin and Wong, {George K.}",
year = "1995",
language = "English",
volume = "28",
pages = "2260--2269",
journal = "Macromolecules",
issn = "0024-9297",
publisher = "American Chemical Society",
number = "7",

}

TY - JOUR

T1 - Chromophore-functionalized glassy polymers with large second-order nonlinear optical responses. Transient dynamics and local microstructure of poly(p-hydroxystyrenes) as assessed by in-situ second harmonic generation techniques

AU - Firestone, Millicent A.

AU - Ratner, Mark A

AU - Marks, Tobin J

AU - Lin, Weiping

AU - Wong, George K.

PY - 1995

Y1 - 1995

N2 - Microstructural relaxation of thin films of the poled, chromophore-functionalized amorphous polymer N-(4-nitrophenyl)-(S)-prolinoxypoly(p-hydroxystyrene) has been studied by in-situ second harmonic generation (SHG) techniques. The temporal and temperature dependence of the SHG intensity decay has been analyzed as a function of poling and processing parameters within the framework of the Kohlrausch-Williams-Watts (KWW "stretched exponential") model. The average SHG relaxation time, τ, increases rapidly upon reduction of the applied poling field strength, with increasing poling time (physical aging), and with decreasing film temperature. The other KWW parameter, β, which reflects the distribution of relaxation times, decreases (the distribution broadens) moderately with increases in the applied electric field strength and strongly with increases in poling time (physical aging). The observed value of β increases (the distribution narrows) with increasing film temperature. These trends and the variation in KWW parameters yield information regarding reorientation dynamics of the tethered chromophore molecules within the polymer matrix and thus on the nature of the system subspace which is explored during relaxation. Both parameters reveal a strikingly narrower distribution of relaxation times/reduced rotational mobility versus chromophore-doped, "guest-host" systems and classify the present materials as Angell "intermediate" glasses. The temperature dependence of the second harmonic signal decay after poling field cessation can be divided into two distinct regions: (i) above Tg, where the dynamics are characteristically nonlinear and best described by the Williams-Landel-Ferry (WLF) equation; (ii) below Tg, where the behavior is linear and modeled adequately by the Arrhenius equation. Analysis of the growth of the second harmonic signal as the poling field is applied yields a similar picture; however, limiting SHG values at temperatures significantly above Tg appear to be influenced by both thermal disruption of chromophore alignment and ion conduction/space charge effects.

AB - Microstructural relaxation of thin films of the poled, chromophore-functionalized amorphous polymer N-(4-nitrophenyl)-(S)-prolinoxypoly(p-hydroxystyrene) has been studied by in-situ second harmonic generation (SHG) techniques. The temporal and temperature dependence of the SHG intensity decay has been analyzed as a function of poling and processing parameters within the framework of the Kohlrausch-Williams-Watts (KWW "stretched exponential") model. The average SHG relaxation time, τ, increases rapidly upon reduction of the applied poling field strength, with increasing poling time (physical aging), and with decreasing film temperature. The other KWW parameter, β, which reflects the distribution of relaxation times, decreases (the distribution broadens) moderately with increases in the applied electric field strength and strongly with increases in poling time (physical aging). The observed value of β increases (the distribution narrows) with increasing film temperature. These trends and the variation in KWW parameters yield information regarding reorientation dynamics of the tethered chromophore molecules within the polymer matrix and thus on the nature of the system subspace which is explored during relaxation. Both parameters reveal a strikingly narrower distribution of relaxation times/reduced rotational mobility versus chromophore-doped, "guest-host" systems and classify the present materials as Angell "intermediate" glasses. The temperature dependence of the second harmonic signal decay after poling field cessation can be divided into two distinct regions: (i) above Tg, where the dynamics are characteristically nonlinear and best described by the Williams-Landel-Ferry (WLF) equation; (ii) below Tg, where the behavior is linear and modeled adequately by the Arrhenius equation. Analysis of the growth of the second harmonic signal as the poling field is applied yields a similar picture; however, limiting SHG values at temperatures significantly above Tg appear to be influenced by both thermal disruption of chromophore alignment and ion conduction/space charge effects.

UR - http://www.scopus.com/inward/record.url?scp=0001453880&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0001453880&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0001453880

VL - 28

SP - 2260

EP - 2269

JO - Macromolecules

JF - Macromolecules

SN - 0024-9297

IS - 7

ER -