LCAM DTM TF TU Liberec,

Hlkova 6, CZ461 17 Liberec, Czech Republic

martina.vikova@tul.cz

Photochromism is a chemical process in which a compound undergoes a reversible change between two states having separate absorption spectra, i.e. different color [1]. In our previous work we have published some solutions of problems of measurement photochromic textile sample by classical spectrophotometer system [2]. Fig. 1 shows optical scheme of present commercial spectrophotometer and Fig. 2 shows our new experimental measuring system.

Main problem with measurement of kinetic behavior of photochromic pigments by classical spectrophotometer is relative long time period between individual measurements (cca 15s) and impossibility of measurement whole color change during exposition without interruption of illumination of sample during measurement. That means classical commercial spectrophotometers enable off-line measurement of kinetic behavior during exposition period and quasi on-line measurement during reversion period.

Based on this problems is possible to obtain only during reversion decay process valid data and growth process (exposition) is affected by high variation of data, as is shown on Fig. 3.