Comparative assessment of stained‐glass windows materials by infrared thermography

Abstract

This paper reports the analyses of infrared thermography images of two stained‐glass windows with the objective of the in situ characterization of this type of artworks. The analyses were carried out by active thermography. The observations revealed that glasses absorbed the long‐wave IR radiation emitted by the halogen lamps and their apparent surface temperature progressively increased. After switching the spotlight off, they experienced a progressive decrease in temperature. Silver stained glasses presented the same thermographic behavior than uncolored glasses because silver nanoparticles were too small or the yellow layer was too thin to produce a different response than the base glass with the IR radiation. The apparent surface temperature of enamels and grisailles depended on their thickness and color. Lead cames maintained an almost constant surface apparent temperature, except those painted that behave in a similar way than enamels. Metallic tin‐lead welds experienced the most important variation in the surface apparent temperature in reflection mode due to the energy reflected by the surface of the weld. Glass defects such as big bubbles were also observed.

Debitus grisailles for stained-glass conservation: an analytical study

“…The temperature variation between both materials was less than 2 °C in all the cases, which indicates a good thermal compatibility. Similar results were observed in previous studies [16,19].…”

“…The IR-thermographic analyses were made in reflection mode on grisailles with different thickness (thicker, medium and thinner) painted on common window glass to understand their thermal behaviour [16][17][18][19]. The samples are showed in Figure 6.…”

Modernist enamels: Composition, microstructure and stability

“…This enhanced absorbance will produce an increase in the overall temperature of the enamel and also a thermal mismatch between particles, enamel glass and base glass. The differences in the thermal expansion coefficients between particles/enamel glass and between the enamel and the base glass are expected to give rise to the formation of cracks Finally, supporting our data, recent studies using Infrared Thermography have shown that dark enamels and grisailles show an increase of the temperature 40% higher than those of the transparent glass [38,39] and about 20% higher than other colour enamels.…”

Impact of solar radiation and environmental temperature on Art Nouveau glass windows

“…These latter materials normally are rough dark paints with iron oxides in their composition. This favors an intense absorption of the thermal radiation, increasing their temperature [36].…”

“…This technique has been applied to evaluate the thermal efficiency of different windows systems [21,22], as well as, to evaluate glasses with different industrial purposes [23][24][25][26], to research fire endurance of tempered glass [27], to study the mechanical defects and the elastic deformations on glass sheets [28][29][30][31][32], and to analyze the efficiency of solar cells [33,34]. The application of IRthermography on historical glasses is scarce [20,32,33]; nevertheless, these studies proved to be a useful tool to evaluate the conservation of historical stained-glass windows [35,36].…”