## 3 Results and Discussion
Finally, according to the overall results obtained, it is possible to propose a new methodological scheme for the estimation of the date of handwritten inscriptions placed on paper using both chromatography and Raman spectroscopy. In general, this scheme can be described as follows. At the first step, the chromatographic measurements are carried out in order to identify the presence \begin{table}
\begin{tabular}{p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline \hline \multirow{2}{*}{**Type of Solvent**} & \multicolumn{2}{c}{**60 Degrees**} & \multicolumn{2}{c}{**Number of Days**} & \multicolumn{2}{c}{**90 Degrees**} & \multicolumn{2}{c}{**Number of Days**} \\ \cline{2-7}  & **Heating Time (h)** & **Peak Area** & **Upon Natural Conditions** & **Heating Time (h)** & **Peak Area** & **Upon Natural Conditions** \\ \hline \multirow{3}{*}{2-Phenoxyethanol} & 7.25 & 905.19 & 3 & 8.5 & 460.97 & 9 \\  & 22.75 & 644.30 & 5 & 23.5 & 204.82 & 35 \\  & 35.25 & 239.19 & 27 & 32.5 & 127.46 & 76 \\  & 43.75 & 159.79 & 54 & 56.0 & 69.72 & More than 120 \\ \hline \multirow{3}{*}{Tetraethylene glycol} & 7.25 & 158.86 & 5 & 8.5 & 135,01 & 7 \\  & 22.75 & 112.34 & 8 & 23.5 & 87,50 & 14 \\  & 35.25 & 77.89 & 20 & 32.5 & 53.74 & 80 \\  & 43.75 & 56.42 & 80 & 56.0 & 36.11 & More than 120 \\ \hline \multirow{3}{*}{Glycerol} & 7.25 & 1304.53 & 5 & 8.5 & 1210.52 & 6 \\  & 22.75 & 1216.86 & 6 & 23.5 & 1087.54 & 8 \\ \cline{1-1}  & 35.25 & 1208.50 & 6 & 32.5 & 589.46 & 14 \\ \cline{1-1}  & 43.75 & 1134.10 & 7 & 56.0 & 284.17 & 30 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Comparison of heating time at different temperatures and storage time under natural conditions with chromatographic parameters obtained for writing inks of different types. or absence of significant amounts of volatile components in the investigated materials. If the chromatographic analysis shows the presence of significant amounts of volatile components, the age of the inscription can be approximately estimated according to Table 7 or the literature available in abundance elsewhere [8; 22; 23; 24]. In the case of a small amount of volatile components, the samples are investigated using Raman spectroscopy techniques. In this step, the recorded Raman spectra are analyzed in the following way:  
1. Raman peaks centered at 1340 and 1266 cm\({}^{-1}\) are attributed to the paper samples containing alcohol- and water-soluble phthalocyanine dyes. 2. Raman peaks centered at 730 and 1580 cm\({}^{-1}\) are attributed to the paper samples containing triarylmethane dyes. 3. Raman peaks centered at 1340 and 680 cm\({}^{-1}\) are attributed to the paper samples containing phthalocyanine pigment. 4. The calculation of ratios of the characteristic Raman peaks of the investigated samples (Table 1). 5. The estimation of the date when the writing ink was placed on the paper using a calibration curve that was previously obtained (Figure 1 and [16]). It should be mentioned that the correctness of the estimated dates was checked by testing the samples provided against the independent databases of three expert organizations. These tests showed that more than 85% of the investigated samples have an agreement in date estimation with the samples provided by the expert organizations (the age of the tested inscriptions was varied from 36 to 120 months). Also, it should be emphasized that the proposed method demonstrates the most successful results in comparison with alternative approaches.