Page 7 - Photoreactive Organic Thin Films

yj CONTENTS

1.5 Azoaromatics of the Pseudo-Stilbene Type 27
1.5.1 Spectroscopic Properties 27
1.5.2 Isomerization of Molecules of the Pseudo-Stilbene Type 29
1.6 The Isomerization Mechanism 31
1.6.1 Azobenzene-Type Molecules 31
1.6.2 Pseudo-Stilbene-Type Molecules 37
1.7 Concluding Remarks 38

2 Ultrafast Dyamics in the Excited States of Azo Compounds
TAKAYOSHI KOBAYASHIANDTAKASHI SAITO

2.1 Introduction 50
2.2 Experimental Section 52
2.3 Results and Discussion 52
2.3.1 1PA2N 52
2.3.2 DMMAB 56

3 Photo-Orientation by Photoisomerization
ZOUHEIR SEKKAT

3.1 Introduction 64
3.2 Photoisomerization of Azobenzenes 65
3.3 Photo-Orientation by Photoisomerization 68
3.3.1 Base Ground Work 68
3.3.2 Theory of Photo-Orientation 69
3.4 Photo-Orientation of Azobenzenes: Individualizable Isomers 79
3.4.1 Reorientation within the trans—>cis Photoisomerization 79
3.4.2 Reorientation within the cis-*trans Thermal
Isomerization 83
3.5 Photo-Orientation of Azo Dyes: Spectrally Overlapping
Isomers 83
3.6 Photo-Orientation of Photochromic Spiropyrans and
Diarylethenes 87
3.6.1 Photoisomerization of Spiropyrans and Diarylethenes 88
3.6.2 Spectral Features of Photo-Orientations 89
3.6.3 Photo-Orientation Dynamics and Transitions Symmetry 89
3.7 Conclusion 96
APPENDIX 3A Quantum Yields Determination 98
APPENDIX 3B Demonstration of Equations 3.12 through 3.15 102