What is ISO 23706 about?
ISO 23706 describes a test method to determine the activation energy (Ea) of photochemical degradation reactions in accelerated weathering tests according to the Arrhenius model in the most comprehensive manner.
NOTE 1- Different property changes, for example, yellowing and surface cracking of one material can have different activation energies.
NOTE 2- ISO 23706, the activation energy is considered as temperature independent for the selected temperature range.
Who is ISO 23706 for?
ISO 23706 on the determination of apparent activation energies in plastic is useful for:
- Plastic manufacturers
- Quality control personnel
Why should you use ISO 23706?
Temperature is an important influencing factor on correlation and acceleration in lightfastness and weathering testing.  The Arrhenius concept describes the influence of temperature on the reaction rate of chemical reactions. ISO 23706 is used (with limitations) to describe the reaction rate of photochemical/weathering reactions.
An important material-specific property to describe the temperature influence on degradation reactions is the activation energy Ea, which describes the required energy barrier for a chemical reaction to occur. Ea is only valid for a specific material and a specific degradation pathway. In weathering, this degradation pathway is usually attributed to a specific property change. The Arrhenius principle is applied to determine the temperature dependency of the thermal degradation of polymers. 
There are some basic test requirements that help to increase the significance of the Arrhenius concept and the determination of the activation energy in accelerated weathering. These requirements are described in ISO 23706.
The determination of activation energies of photochemical degradation processes allows including the temperature into the evaluation and correlation of different weathering experiments as a quantitative factor. Knowing the activation energy improves the reliability and predictive value of artificial weathering.
