The geothermal history of natural resins from different geographical locations was studied in terms of their age assessment and structure–properties relations. Thermal properties of resin samples were analyzed by thermogravimetry (TG) and differential scanning calorimetry (DSC), whereas infrared spectroscopy was used for analysis of the resins structure. Relative dependence between thermal parameters and degree of resin maturity was found. Glass transition process and thermal events during heating of raw materials were investigated by advanced stochastic-modulated DSC method, known as TOPEM ® , that allowed to determine the “true” glass transition temperature in the first heating scan. It was observed that TG method is insufficient for the resin age assessment, although it was found that there is a certain correlation between the glass transition temperature, estimated by TOPEM ® DSC, and resin age. The natural resins proved to be reactive and sensitive material under elevated temperatures up to 200 °C. Subsequent processes of evaporation, relaxation and curing without significant mass loss related to degradation were observed during heating of resin samples. The aging rate in natural resins has been assessed using the intensity of 1730 cm −1 and 1646 cm −1 band after deconvolution of IR spectra. It may be assumed that younger resins are characterized by relatively higher reactivity (higher number of C=C bonds) and lower oxidation level.

中文翻译：

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天然树脂的成熟过程记录在其热性能中

从年龄评估和结构-性质关系方面研究了来自不同地理位置的天然树脂的地热历史。树脂样品的热性能通过热重 (TG) 和差示扫描量热法 (DSC) 进行分析，而红外光谱用于分析树脂结构。发现了热参数和树脂成熟度之间的相对依赖性。通过先进的随机调制 DSC 方法（称为 TOPEM ® ）研究原材料加热过程中的玻璃化转变过程和热事件，该方法允许在第一次加热扫描中确定“真实”玻璃化转变温度。据观察，TG 方法不足以进行树脂老化评估，尽管发现玻璃化转变温度（由 TOPEM ® DSC 估算）与树脂老化之间存在一定的相关性。事实证明，天然树脂在高达 200 °C 的高温下是反应性和敏感材料。在树脂样品加热期间观察到随后的蒸发、松弛和固化过程，而没有与降解相关的显着质量损失。使用红外光谱解卷积后 1730 cm -1 和 1646 cm -1 波段的强度评估了天然树脂的老化率。可以假设，较新的树脂具有相对较高的反应性（较高数量的 C=C 键）和较低的氧化水平。在树脂样品加热期间观察到随后的蒸发、松弛和固化过程，而没有与降解相关的显着质量损失。使用红外光谱解卷积后 1730 cm -1 和 1646 cm -1 波段的强度评估了天然树脂的老化率。可以假设，较新的树脂具有相对较高的反应性（较高数量的 C=C 键）和较低的氧化水平。在树脂样品加热期间观察到随后的蒸发、松弛和固化过程，而没有与降解相关的显着质量损失。使用红外光谱解卷积后 1730 cm -1 和 1646 cm -1 波段的强度评估了天然树脂的老化率。可以假设，较新的树脂具有相对较高的反应性（较高的 C=C 键数）和较低的氧化水平。