Abstract:
Raman microscopy is used in the analysis of glaze on a number of samples that include blue and white ceramic shards, a tile
from the Citadel of Algiers and intact Ming plates. The use of the glaze depth profiling method for the study of interfacial
pigments on these samples [J. Raman Spectrosc. 2007; 38: 1480] prompted the study of the glaze on the same set of samples
to determine glaze type dependence of this method. Using the index of polymerization (Ip) which is closely correlated with
glaze composition and processing temperature, it is shown that processing temperature could be estimated from a low of
about 600 C for some of the unknown archaeological shards to about 1000 C or above for the Ming porcelain shards. Two
intact porcelain plates from the Hongzhi (1488 – 1505) and Wanli (1573 – 1620) Ming imperial periods from the J. A. van
Tilburg Museum of the University of Pretoria have been studied, and glaze/glass transition temperature was estimated to
be above 1000 C, consistent with historical data. A SnO2-based glaze tile shard from the Citadel of Algiers was also successfully
probed, and results indicated a much lower sintering temperature.
