Steric Effects in Photochromic Polysiloxanes with Spirooxazine Side Groups

Alexander Zelichenok; Frida Buchholtz; Shlomo Yitzchaik; Judith Ratner; Mark Safro; Valeri Krongauz

doi:10.1021/ma00038a025

Steric Effects in Photochromic Polysiloxanes with Spirooxazine Side Groups

Alexander Zelichenok, Frida Buchholtz, Shlomo Yitzchaik, Judith Ratner, Mark Safro, Valeri Krongauz

Research output: Contribution to journal › Article › peer-review

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Abstract

Synthesis and properties of linear and cyclic polysiloxanes with photochromic spirooxazine side groups were investigated. The photochromic groups were connected to the main chains through a flexible (CH₂)_n spacer. The number of photochromic groups that can be incorporated in the polymer by a polymer analogous reaction is restricted for the short spacer (CH₂)₃ to ~50%, while the photochromic groups with the longer spacer (CH₂)₆ can be added to practically each polymer unit. The rates of the thermal decoloration reactions are also determined by the spacer lengths and the spirooxazine content. At high content, a deviation from first-order kinetics was observed for the color decay. The effects are explained by the steric interactions of the bulky photochromic groups. Computer simulation of the molecular movement in the macromolecules confirmed the explanation.

Original language	English
Pages (from-to)	3179-3183
Number of pages	5
Journal	Macromolecules
Volume	25
Issue number	12
DOIs	https://doi.org/10.1021/ma00038a025
State	Published - 1 Jun 1992
Externally published	Yes

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abstract = "Synthesis and properties of linear and cyclic polysiloxanes with photochromic spirooxazine side groups were investigated. The photochromic groups were connected to the main chains through a flexible (CH2)n spacer. The number of photochromic groups that can be incorporated in the polymer by a polymer analogous reaction is restricted for the short spacer (CH2)3 to ~50%, while the photochromic groups with the longer spacer (CH2)6 can be added to practically each polymer unit. The rates of the thermal decoloration reactions are also determined by the spacer lengths and the spirooxazine content. At high content, a deviation from first-order kinetics was observed for the color decay. The effects are explained by the steric interactions of the bulky photochromic groups. Computer simulation of the molecular movement in the macromolecules confirmed the explanation.",

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T1 - Steric Effects in Photochromic Polysiloxanes with Spirooxazine Side Groups

AU - Zelichenok, Alexander

AU - Buchholtz, Frida

AU - Yitzchaik, Shlomo

AU - Ratner, Judith

AU - Safro, Mark

AU - Krongauz, Valeri

PY - 1992/6/1

Y1 - 1992/6/1

N2 - Synthesis and properties of linear and cyclic polysiloxanes with photochromic spirooxazine side groups were investigated. The photochromic groups were connected to the main chains through a flexible (CH2)n spacer. The number of photochromic groups that can be incorporated in the polymer by a polymer analogous reaction is restricted for the short spacer (CH2)3 to ~50%, while the photochromic groups with the longer spacer (CH2)6 can be added to practically each polymer unit. The rates of the thermal decoloration reactions are also determined by the spacer lengths and the spirooxazine content. At high content, a deviation from first-order kinetics was observed for the color decay. The effects are explained by the steric interactions of the bulky photochromic groups. Computer simulation of the molecular movement in the macromolecules confirmed the explanation.

AB - Synthesis and properties of linear and cyclic polysiloxanes with photochromic spirooxazine side groups were investigated. The photochromic groups were connected to the main chains through a flexible (CH2)n spacer. The number of photochromic groups that can be incorporated in the polymer by a polymer analogous reaction is restricted for the short spacer (CH2)3 to ~50%, while the photochromic groups with the longer spacer (CH2)6 can be added to practically each polymer unit. The rates of the thermal decoloration reactions are also determined by the spacer lengths and the spirooxazine content. At high content, a deviation from first-order kinetics was observed for the color decay. The effects are explained by the steric interactions of the bulky photochromic groups. Computer simulation of the molecular movement in the macromolecules confirmed the explanation.

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Steric Effects in Photochromic Polysiloxanes with Spirooxazine Side Groups

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