Synthesis and properties of two photochromic dyes

• Main Author: Ng, Shihui.
• Other Authors: School of Materials Science and Engineering
• Format: Final Year Project
• Language: English
• Published: 2012
• Subjects: DRNTU::Engineering::Materials::Photonics and optoelectronics materials
• Online Access: http://hdl.handle.net/10356/48810
• Institution: Nanyang Technological University

Photochromic dyes have been extensively studied due to their demands and applications especially in the ophthalmic lens industry. Photochromic lenses respond reversibly to the light intensity; darkens with ultraviolet exposure and changes back to its original state with reduced exposure. Two photochromic dyes are synthesized and properties in colour change are observed. Photochromic dyes when exposed to ultraviolet light, it experiences a transformation from its colourless closed form isomer to the coloured opened form isomer. Identification of intermediate products in the synthesis of Dye 1 and 2 are carried out using techniques such as Electrospray ionization mass spectrometry (MS-ESI), Proton Nuclear Magnetic Resonance (H-NMR), Mass Spectrometry Time -of-Flight (MS-TOF). Finally, Ultraviolet-Visible (UV-Vis) Spectroscopy is conducted on both Dye 1 and 2, and properties are observed. However, transition time of the dyes from coloured to its colourless state, need to be shortened for applications.