Phosphorescence of thermally altered human bone

Area of Science:

• Forensic Anthropology
• Biophysics
• Materials Science

Background:

• Bone exhibits photoluminescence, useful in analyzing thermally altered human remains.
• Photoluminescence encompasses fluorescence and phosphorescence, with phosphorescence often having a longer decay time.
• The contribution of long-decay phosphorescence to bone's photoluminescence and its temperature dependence were previously unknown.

Purpose of the Study:

• To investigate if thermally altered human bone emits long-decay phosphorescence.
• To determine if phosphorescence aids in estimating the temperature of heated bone fragments.
• To assess the influence of temperature, exposure duration, surrounding medium, bone type, skeletal element, and excitation light on phosphorescence.

Main Methods:

• Bone samples were heated from room temperature to 900°C in air or adipose medium.
• Skeletal elements from cremated human remains were analyzed.
• Samples were illuminated with different light bandwidths and visually inspected for photoluminescence and phosphorescence.
• Long-decay phosphorescence intensity was scored, and samples were photographically documented.

Main Results:

• Thermally altered human bone fragments were observed to phosphoresce.
• Phosphorescence intensity was more sensitive to temperature than to exposure duration, surrounding medium, or skeletal element.
• Ultraviolet light yielded the most temperature-correlated data, showing changes in phosphorescence intensity and emission spectrum.
• Long-decay phosphorescence and short-decay fluorescence/phosphorescence occurred concurrently, with temperature-dependent variations.

Conclusions:

• Phosphorescence is a significant contributor to the photoluminescence of thermally altered human bone.
• Observable phosphorescent characteristics can assist in estimating the temperatures of cremated human skeletal fragments.
• This finding enhances forensic anthropological investigations of burned remains.