Chemistry Research Review Meeting: Photochromic and Thermochromic Pigments Held in Port Hueneme, California on 11 February 1986.
Abstract
A chemistry and physics review meeting was held to Navy and university contractor work on the elucidation of reversible thermochromism in metal tetraiodomercurates (TIM) and reversible photochromism in benzoindolinopyrospirans(BIPS). The observe thermochromism in silver (I), copper (I), lithium, sodium, thallium, gold (I), potassium, cesium and rubidium TIMS was determined to be due to perturbation of the charge transfer spectra originating from electrons in the filled iodine orbitals interacting with those in the unfilled mercury orbitals. The observed increased increase in conductivity of the solid metal TIMs was found to be due to a transition from an ordered tetrahedral structure to a disordered octahedral structure at the phase transition temperature. The presence of atomic defects or holes in the crystal lattice allows the metal cation (copper(I), gold (I) and silver) to migrate, producing a current. Differential scanning calorimetry (DSC), was used to determine the quantitative phase transition temperature. Experiments conducted on the BIPS in polar and non-polar solvents, plus electron paramagnetic resonance (EPR), mass spectra (MS), and nuclear magnetic resonance spectra (NMR) under different condition, led us to believe that the photochromism is probably not due to free radical ring opening but may be due to charge separation from a zwitterion type structure in which the indoline nitrogen bears the positive charge and the benzopyran oxygen bears the negative charge. (Keywords): Coatings; Pigments; Solar Energy; Photochromism; Thermochromism; Energy absorbance; Energy reflectance; Chemical synthesis, and Thermal semiconductors.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 11, 1986
- Accession Number
- ADA178495
Entities
People
- Thomas Novinson
Organizations
- Naval Facilities Engineering Service Center