Atlas revolutionary S³T technology is now available for both Ci4400 and Ci5000 Weather-Ometers. S³T™ is a system that measures the specific specimen surface temperature during accelerated laboratory weathering.
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Surface temperatures in photodegradation and weathering
• Surface temperature is a critical factor for the rate of photochemical reactions
• Specimen properties (color, IR absorbance, material density, thickness, sample backing) influence the surface temperature and the degradation behavior
• The measurement of individual surface temperatures with thermocouples is complex and not practical for multiple samples especially in accelerated weathering instruments
• Surface temperatures are usually neglected or roughly estimated based on black and white standard panel reference temperatures
• The S³T™ facilitates the continuous determination of multiple individual specimen surface temperatures throughout the duration of the exposure
The S³T™ Measurement System helps to optimize test parameters and provides:
• Better reproduction of natural conditions (heat uptake, color distribution)
• Better control of test parameters to avoid overheating of specific specimens
• Continuous tracing of the specific sample temperature allowing for the immediate detection of property changes such as darkening without disruption of the test
• Investigation of specific sample characteristics e.g. cool pigments, IR-reflective coatings or effectiveness of heat and light stabilizers
Knowing the surface temperature of materials assists experimenters with the following important analyses:
• Ranking of materials
• Comparison between different exposures
• Estimation of theoretical acceleration factors (based on the Arrhenius concept)
• Determination of activation energies of photochemical degradation reactions
• Reproducibility of weathering data
• Planning and evaluation of correlation studies S3T™ Measurement System design details:
• The core of S³T™ is an integrated stationary IR pyrometer which measures surface temperatures based on the radiant emittance of the test specimen
• Calibration of S³T™ is traceable to a recognized standards body
• The accuracy has been validated for various basic standards using thermocouples
• S³T™ can operate continuously throughout the entire test duration
• S³T™ is available in the Ci4400 and Ci5000 Weather-Ometers®
S3T™ Measurement System data collection process:
• Special specimen holders are equipped with an RFID tag
• Specimens rotate around a stationary IR pyrometer
• An RFID reader identifies the center position of each specimen in the middle specimen rack and assigns the individual temperature readings
• S³T™ temperature data can be viewed in graph or table format using the integrated Weather-Ometer® software
• S³T™ temperature data can be exported into a spread-sheet or WXView II for detailed analysis
