Conventional reactions used to study kinetics can be expensive, environmentally unfriendly, and not of immediate relevance to students. In this presentation we show how UV sensitive beads (Educational Innovations UV-750) and thread (Solar Active) can be use to demonstrate reaction kinetics. Students record the reflection spectra of the beads and threads using a fiber optically coupled visible spectrometer (Spectrovis Plus) along with a white light source and UV-lamp. The decay in the absorption of visible light, as the beads return from an excited state (colored) to the ground state (white), can be modeled using first-order reaction kinetics. A comparison of reaction rate constants can lead to a qualitative comparison of the types of dyes used in the materials. This experiment also shows how absorption of complimentary colors leads to color perception. The experiment is well suited for introductory chemistry classed for both majors and non-majors in science.

Relaxation kinetics of UV sensitive materials

243rd National Meeting (2012)

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